6510/a. Graphics Computer System. Variable Density Disk Drive Controller. Part No Rev.

Transcription

1 65/a Gaphics Compute System Vaiable Density Disk Dive Contolle efeence Guide Pat No ev. This document descibes the use of two types of Floppy Disk Dive Contolles in an 65/a Gaphics Compute System: a Vaiable Density Disk Dive Contolle and a Single Density-only Disk Dive Contolle. These modules contol diect memoy access (DMA) data tansfe between system main memoy and eight inch floppy diskette dives. Up to fou dives, installed in 85, 852 and 855 units, can be contolled. This hadwae, in conjunction with appopiate softwae, suppots the following fomats: IBM 37 single-sided, single density; 37D singlesided, double density; IBM 374/2D double-sided, double density. This hadwae/softwae subsystem is completely compatible with oiginal 65/a Single Density, non-dma configuations. P. TEAK COF.POF.ATIC!: Scottsdale, Aizona

2 TEAK COPOATION believes accuate. In no event will whethe diect o indiect infomation, including, wi claims of patent, copyigh is ganted heeby fo the TEAK. TEAK eseves the heein at any time without that the infomation contained heein is TEAK be liable fo any losses o damages, esulting fom the use of such ' thout limitation, losses aising fom t, and tademak infingement. No license use of any patent o patent ights of ight to update the infomation contained futhe notice. Inn in«?k8tjon f "tained 5e»:ein is Popietay to TEAK COPOATION and oust be teated as confidential. It may not be disclosed to COPOATIONS6d ^ "^ pupse without the witten consent of TEAK 85/a GAPHICS COMFUTt SYSTEM VAIABLE DENSITY DISK DIVE CONTOLLE EFEEE GUIDE FIST EDITION COPYIGHT 9 BY TEAK COPOKATION "ALL IGHTS ESEVED" TEAK is a tademak of TEAK Copoation. DEC, PDP-, T- and LSI- ae tademaks of DIGITAL EQUIPMENT COPOATION.

3 J CONTENTS I SECTION pag E. Geneal Desciption - E. Diskette Fomats & Dive Attibutes*.!*"!'. f~ El.2 Media Consideations...****' \\ E2. Contolle Desciption '" Ei. E2. Pocesso Inteface.*.*.'!...'...'**.** c ll'\'l J?Ppy,Disk status egiste ( OECS)'. '. '.'.!!!!'.'.'.'.! E6 E2..2 Multi-Pupose Stack (OEMS) DKA Contol/Status egiste (QBDC)...!** E7 E2..4 Teminal Count egiste (OETC) -? E2..5 Bus Addess egiste (QBBA) \ *'. * \\ \ \ \ \ \ \ \ e{ E3. Diskette & Tack Geomety E6 E*». Contolle Instuction Set Q E4. Byte Desciptions %l E^.2 Bit Desciptions!.'!!""".*.!!*!"!'El E^.3 Instuction Desciptions.* -ip E^.3. ead Data Instuction \\\\Y.\\\\\ E2 E^4.3.2 ead Deleted Data Instuction..*."".'*'.'.'.'.''.'." E4 E^J.3.3 ite Data Instuction E5 E^.3.^ ite Deleted Date Instuction..'.*'*.*.'.'*.'.*'*.' E6 ^ E^.3.5 ead A Tack Instuction.!!!"'*** E7 v E^.3.6 ead ID.Instuction..'*!''.*!."" E6 E4.3.7 Fomat A Tack Instuction EQ E^.3.8 Scan Instuctions E?n E^.3.9 Seek Instuction \\\\\ 23 E^.3. ecalibate Instuction...*".'*.'.*!!!! E2^ E^.3. Sense Dive Status Instuction..*,!! E24 E4.3.2 Sense Inteupt Status Instuction 25 E4.3.3 Specify Instuction E26 E4.il Invalid Opeation...*! E26 E5. Boot OM

4 d Table List Of Tables PaEe E. ID Infomation hen the CPU Teminates an Instuction E27 2. Tansfe Capacity E2B 3* Fomatting Vaiables ^ 2 6 E4. SH & SN Status Bits,.. E29 E5# Status egiste Desciption E29 6. Status egiste Desciption E3C E7. Status egiste 2 Desciption E3 E8. Status egiste 3 Desciption E32 Name Poga. Listings Page Vaiable Density Floppy Disk Contolle (FDC) Boot OM Code,. Figue Numbe List Of Figues E. Vaiable Density Disk Contolle Q-Bus Inteface egistes E2. QBCS, QEMS egistes E3. OBDC, OBTC, OBBA egistes E^. Diskette & Tack Geomety p

5 APPENDIX E. Vaiable Density Disk Dive Contolle efeence Guide E. Geneal Desciption The 85/a system utilizes eight inch magnetic floppy diskettes fo SJfl/J"?"*; ThlS docuinent descibes the use of eithe of two Disk to??^s: 8.standad» Single Density-only Disk Dive J?l? Ei nin?tl.na' Vaiable Density Disk Dive Contolle I«J» liable Density Disk Dive Contolle, and its appopiate softwae handle, intefaces to single and dual head dives h suppots the IBM 37/2D fomat fodousjs densityf mo5i?ild JJ!?CV dulation (MFK) ecodi"e. as well as the IBM 374 8wie DpntJtv'?qU??Cy modulation <FM) fomat. As a esult, the Vaiable Density Contolle suppots the tansfe of data to and fom bll»l III i" ^he/ollowjne manne: single-sided, single-density (i2c llltla.. 5 * l\ S?6le-sided, double-density (52 bytes pe secto); and double-sided, double-density (52 bytes pe secto). The isfj?i)?nsjty;?nly Contolle has all the attibutes of the Vaiable The hadwae/softwae subsystem can contol up to fou dives whose diskettes have combinations of the peviously descibed side and SiskeM^eted istovj""" ecgni2e the ^ «hen tne JJS»yjIiiblf?!nslty/and the s^ele Density-only) Contolle povides, at the secto level, DMA data tansfe between the main jemoy in the 85 unit and up to fou diskette dives. The Contolle suppots paallel-seek opeation on all fou divessimultaneous multiple heads-down opeation; multi-secto and multitack data tansfe; and diskette fomatting fo the soft-sectoed ecoding mode. Data tansfe ates ae 25 K-bits pe second fo FK encoding and 5 K-bits pe second fo MFK encoding! The Contolles also povide the electonics necessay to inteface the diskette dives to the 85/a system bus (identical to the LSI- Q-bus), plus ecod and ecove infomation in single density fomats (and double density fomats - Vaiable Density Contolle only). I5f Coones also contain a 255 wod (b-bit) initial boot OM. This OM, and all applicable egistes of the Contolles, ae accessed via Bank 7 (/ Page) of the LSI- addess space. SS!!.?"?!? consjsts of: a dual-width (8.9 in. V x 5.2 in. H) nodule, installed in a slot of the 85 unit backplane, and an Extenal Inteface Boad (EIB), installed on the ea suface of the ftlis ""ihc?2us,inte Onnect cables- EIBs ae also povided fo the 852 and 855 units. DIP switches on the EIBs ae used to assign a dive as unit,,2, o 3. El

6 Access Times Single Head Dive Dual Head Dive «e.d Load Tines: 35..UMseiond's si s Maximum Eo ates: ecoveable eo pe "9 bits non-ecoveable eo pe 2 bits El.2 Media Consideations By means of the infomation stoed on Tack of all Tfak,.mni4.H IBM-compatible diskettes, the use can access vaies fomats Pll diffeent diskette media, simultaneously? this lilt lulls llilus dave and media types to be used simultaneously. vaious E3

7 . Diskette Fomats & Dive Attibutes The following media fomats ae used by TEAK: Single-density Cylindes (Total) 77 Tacks (Total) 77 Index Tack(s) Sectos/Tack 26 Data bytes/secto 28 Sectos/Diskette 22 Data bytes/diskette 256,256 Single-sided Double-density * ,8 Double-sided Double-density 77 5* * «2332,73,34* Tack is single-density, 28 bytes/secto, 26 sectos. fjsl?' y^n2e ' JS fin6le-density, 28 bytes/secto, 26 sectos. " Side, Cylinde, is double-density, 256 bytes/secto, 26 sectos. The dive assemblies used (single-head & dual-head) poduce the following attibutes: otational Speed: otational Diection (as would be seen fom the label side of a diskette): Tacks/Inch: ead/ite Tack idth: Inside Tack adius: 36 PK CK 48.2 in in. ecoding Density (inside tack) Flux Density (inside tack) 32 bpi (single density) 64 bpi (double density, MFM) 64 fci (single density) 64 fci (double density, MFM) Encoding Methods: FM (Single Density) MFM (Double Density) Data Tansfe ates: 25 K-bits/S (Single Density, FM encoding) 5 K-bits/S (Double Density, MFM encoding) Aveage Latency: 83 milliseconds Aveage Access Time: 26 milliseconds 2

8 2. Contolle Desciption The Floppy Disk Contolle module (FDC) is capable of tansfeing a minimum of one byte to a maximum of 6,384 bytes, in the Diect Memoy Access (DMA) mode. Data anywhee in main memoy can be tansfeed to the sectos of a diskette; convesely, data foc any of the diskette sectos can be tansfeed to any of the locations*in main memoy, (Bank 7 is nomally eseved fo peipheal I/O device addesses.) The DMA data tansfe is accomplished, witn-a minimum of pocesso ovehead. The FDC convets the data bytes fom the main memoy into a seial bit steam; this data steam is then inteleaved with a seial clock bit steam. The esultant clock/data envelope is then ecoded on a diskette as a seies of flux changes. hen a diskette is ead, the flux changes ae e-conveted to a clock/data bit steam. A data ecovey cicuit sepaates the clock and data bit steams to ecove the data bits. The FDC then convets the seial data bit steam into data bytes fo stoage in main memoy. The FDC will execute the following 5 instuctions: Bead Data ite Data Sense Inteupt Status ead ID ite Deleted Data Sense Dive Status ead Deleted Data Scan Equal Seek ead a Tack Scan High o Equal Specify Fomat a Tack Scan Low o Equal ecalibate (estoe to Tack ) The FDC contains five Q-bus accessible egistes, as shown in Figue E-. The bits of the ead-only FDC Status egiste (QBCS) indicate data tansfe diection, opeating mode (DMA, non-dma), data validity, FDC status and dive status. The Multi-Pupose Stack (OEMS) is used to stoe bytes in a cetain sequence. These bytes specify the paametes of a diskette data tansfe (i.e., physical location, data steam length, encoding method, etc.) and the type of opeation to be pefomed. As shown in Figue E-, DMA is contolled by 3 Q-bus accessible egistes. A 6-bit Bus Addess egiste (QBBA) is loaded with the stating addess that specifies the beginning location, in main memoy, fo a data tansfe. The lowe 4 bits of a 6-bit Teminal Count egiste (QBTC) ae loaded witn an ending, o teminal count value, that specifies the length of the data block to be tansfeed (the uppe 2 bits specify ead o wite opeation). hen the DMA tansfe commences, the stating addess is put on the Q-bus and a DATI o DATO(B) opeation occus. The addess is then incemented and the ead o wite opeation is epeated. This sequence continues until the numbe of data tansfes equals the value (plus one) loaded in the QBTC egiste. At that time, the tansfe is completed. The module also contains an 8-bit DMA Contol/Status egiste (QBDC). This egiste is used to enable the DMA and Floppy Disks; to enable the DMA inteupt; and to set the data diection (i.e., memoy ead o wite).

9 2. Pocesso Inteface ( The FDC can tansfe a single byte (single DMA cycle), o multiple bytes (multiple-dma cycles; i.e., DMA tansfe). The addesses of the Q-bus accessible egistes, ae as follows: Q-fius Addess (octal) Mnemonic Function 2J2SS2 QBCS Floppy Disk Status egiste 72 OEMS Multi-Pupose Stack BDC DKA Contol/Status egiste 2J2S2J ETC Teminal Count egiste 76 QBBA Bus Addess egiste Initial bootstap OM The FDC is capable of executing 5 instuctions, es listed in Pat E2 of this document. Desciptions of these instuctions ae contained in Pat E4. Each instuction equies multiple-byte tansfes to set up, execute, and complete an instuction. As a convenience, an instuction may be consideed as consisting of thee phases: Command Phase: The FDC eceives all infomation, equied to pefoi. a paticula opeation. /m* Execution Phase: The FDC pefoms the opeation. esults Phase: Afte completion of the opeation, status and othe housekeeping infomation is made available. Duing the Execution phase, data bytes ae tansfeed between the FDC and a dive. The fomats of OBCS and QBMS ae shown in Figue E-2. One egiste monitos the FDC status, the othe egiste location is actually a stack, used to stoe and etieve data duing the Command and esults phases of an instuction. The fomats of QBDC, QBTC and QBBA ae shown in Figue E-3. These egistes ae used fo DMA opeations. E5

10 E2.. Floppy Disk Status egiste (QBCS) upose Stack (QBMS). This altenating QBCS-ead/QBMS-wite (duin accept^ new instuction. Duing the Execution phase, Q^fneed net octfl!s ^^ fij th l6 byte f a C"bus wod at ^cation 7OOC, QBCS bits though 3 eflect dive status; that is, whethe o not to tack)! '^ (ln Seek mode' t m Ve the'ead/wite b«d Jon t?ack indicates Mhethe the FDC is b"y with a ead o a wite QBCS bit 5 indicates the opeating mode. This bit is set only 4. k*< $ indicates data tansfe diection. A "" means that data is being tansfeed fom the Q-bus to the FDC; a is being tansfe ^cfijemta!^ S6t> indicates thst BKS is. eady to send o E2..2 Multi-Pupose Stack (QBMS) QBMS is a stack (of 8-bit egistes) that is pushed and popped, espectively, duing the Command and esult phases of an instuction into H«ti!f»iO equjes J** a specific sequence of bytes be loaded into, and ead fom, the stack. As shown in Figue E-2, a o 2 byte coojand code (that specifies a paticula instuction)fbs.t II loadeo fist, and then followed by to 7 configuation bytes. Afte instuction execution, status bytes (whose bits specify any eos that had occued duing execution) and secto ID bytes (that eithe duplicate the secto ID bytes that wee loaded duing the Command phase o have been changed because of instuction temination) ae etuned to the stack. QBMS must be ead (and intepeted) to poceed to a new instuction. The byte codes fo QBMS ae descibed in Pat the lowe byte of a Q-bus wod at E6

11 E2..3 DMA Contol/Status egiste (QBDC) QBDC oust be pogammed afte QBTC and QBSA egistes have been L!ln?^ed:hBD*CKS Cleaed (eset) ^eneve a eset instuction is executed, when the system is eset (boot switch depessed), o when powe is cycled. Bit of QBDC oust be set to enable the DKA wl ltlujvng*?macyl QBDC bit will be c!ea? tj \ead QBDC bit ij detemines data diection duing a DMA cycle: if pogammed to ««, data will be tansfeed fom memoy'to diskette. Jnth^On?*?: 5 6 Jnd.-7 BUSt be Pogamed to the states shown in the QBDC bit nap of Figue -3 to pevent spuious opeations. lllltllwjl ml f"? wiiten t» the I *' ^te of a Q-bus wod at location 72, octal, and consumes a single DATI o DATOB bus cy oi e E2..4 Teminal Count egiste (QBTC) QBTC must be pogammed with a numbe that is one less than the desied numbe of byte tansfes. Fo instance, if "" is loaded, e ni?6i!l? Cyle Ould occu> A maximum of 6.38U bytes ae allowed ^ik pe una tansfe. Ihl Jinn!. l\*lts f?ftc.!e USed fo the te in*l count numbe; the uppe 2 bits specify the data diection duing a DMA opeation. Only two combinatoial states ae allowed fo bits 6 & 7, as shown in the QBTC bit map of Figue E-3. E2..5 Bus Addess egiste (QBBA) QBBA oust be pogammed vith the addess of the fist memoy byte location to be accessed duing the DMA opeation. Duing the opeation, the Contolle will incement, (by one), the addess put on the bus, until the desied numbe of byte locations (specified by the value loaded into the lowe 4 bits of QBTC) have been accessed. QBBA can be loaded with any stating addess, howeve, Bank 7 (6 to 77777, octal), of the LSI- addess space, is geneally eseved fo I/O device addesses. Note: QBTC and QBBA ae both 6-bit egistes that ae witten to the lowe byte of a Q-bus wod at espective locations 74 and 76, octal. Two DATOB bus cycles ae equied to load eithe egiste. f E7

12 3. Diskette & Tack Geomety ( wilum of a" diskettes used with the 85/a system t.cks of s cylinde tu., fsste, because the opposini the ead/yite heads. accessed, sequentially, without moving «vld.d into 26 S I i / tysemeuo^i?; --! «o-5.s fs:i»;:5.ss.?d.;. 6

13 E4. Contolle Instuction Set The FDC has a epetoie of 5 instuctions, as follows: Specify Sense Inteupt Status Sense Dive Status ead * Tack Fead dieted Data JSn^i! (estoe Scan High o Equal Scan Low o E The FDC equies multiple-byte tansfes to execute the SSSJi^-SS;! (and cetain bits of b E4. Byte Desciptions C; Cylinde No. : The cuent/selected cylinde numbe ( to 76; H; Head No. : The selected ead/wite head ( = Side ; = Side ) «; ecod No. : The secto (ecod) numbe (He 26, single density; to 5, double density) ' N; Numbe : The numbe of data bytes/secto ( fo single density, 2 fo double density) witten into a secto. EOT; End Of Tack: The final secto numbe (5 o 26) of a tack. GPL; Gap Length: The Post-ID and Post-Data gap lengths; that is, the inte-ecod gaps. GPL is is equated to a binay magnitude; see Table E3 fo ecommended values. DTL; Data Length: The numbe of data bytes witten into o ead fom 8 secto when N. If DTL defines a data length smalle than that which was defined by N when N was not zeo, the ead o wite tansfe will cease when the DTL value is eached. The FDC will continue to ead o wite (with zeoes) the emainde of the data field to pefom the CC function. hen N is not zeo, DTL must be set to all "'s" (i.e.. FF. hex o 377, octal). ' ' f E9

14 STP; Scan Tack, Pocesso: Duing a Scan (High, Low, o Equal) instuction,the data bytes in a secto ae compaed with data bytes fom the Q-bus. If STP =, the data bytes fom contiguous sectos ae compaed. If STP =2, data bytes fom altenate sectos ae compaed. STO; Status : These ae fou egistes that ae ead at.the ST; Status : beginning of the esult phase of an instuction. The ST2; Status 2: egistes that ae ead depend on the paticula ST3; Status 3: instuction. The bits of the egistes indicate what eos (if any) occued duing the instuction execution, and whethe the instuction teminated nomally o abnomally. See Tables E5 though E8 fo a desciption of these egistes. SC; Sectos/Cylinde: Duing a Fomatting instuction, SC detemines the numbe of sectos to be witten on a (tack); (5 fo double density; 26 fo single density). D; Data: Duing a Fomatting instuction, D is the byte patten that is witten into the data fields to define the data field locations on a tack. D can be any patten. PCN; Pesent Cylinde No. : PCN is ead duing the esult phase of e Sense Inteupt Status instuction and epesents the pesent position of the ead/wite head(s) (i.e., at Cylinde though 76). N; New Cylinde No. : N is the cylinde numbe to which the ead/wite head(s) will move duing a Seek instuction. N is loaded duing the Command phase of Seek with value though 76. E4.2 Bit Desciptions MT; Multi-Tack: A command code bit in the ead, ite and Scan instuctions. hen MT s, data will be tansfeed to/fom both tacks of a cylinde, stating at Secto, Side and completing at Secto L (last secto) of the opposing tack on Side, of a doudle sided diskette. MF; FM o MFK Mode: A command code bit in the ead, ite, Scan and Fomat instuctions. hen MF s, the FM node is selected; when MF s, the MFM mode is selected. SK; Skip: A command code bit in the ead (except ead ID) and Scan instuctions. hen executing a ead Data o a Scan instuction, and SK, the FDC will skip ove, (not ead), a secto that has a Deleted Data Addess Mak (DDAM). The CC bits of a skipped secto ae not checked. At this time, if a Scan instuction is ^ executing, the Contol Mak (CM) bit of the ST 2 f egiste is set, to indicate that a DDAK had beeencounteed. E

15 HD; Head hen executing a ead Deleted Data instuction, and SK, the FDC will skip ove a secto that has a Data Addess Mak. hen executing a ead a Tack instuction, the SK bit is ignoed. hen SK, the FDC will ead the field 'that would have been skipped ove, and then teminate the instuction. At this time, the CM bit of ST 2 will be set. A command code bit that indicates the selected head ( = Head ; = Head ). This bit must have the same value as H, the Head No. byte. HLT; Head Load Time : Seven bits of a command code of the Specify instuction. HLT contols the head load time of a dive (defined as the inteval between the assetion of a head load signal and the commencement of a ead/wite opeation). HLT is pogammable in 2 millisecond incements ove the ange 2 ms to 254 ms; it is equated to a binay magnitude: 2 ms = ; 254 ms = FE,hex 376,octal. HUT; Head Unload Time: Fou bits of a command code of the Specify instuction, pogammable in 6 millisecond incements ove the ange 6 ms to 24 ms. (6 ms = (^ ; 24 ms = OF,hex = 7,octal). HUT stats at the end of a / execution phase. Note: Hadwae causes a head to emain loaded fo 6 ms afte the end of a / instuction execution phase. ST; Step ate Time: Fou bits of a command code of the Specify instuction. ST contols the head stepping ate (defined as the time it takes to move fom tack to adjacent tack). ST is pogammable in millisecond incements; it is equated to a binay magnitude: ms = F,hex 7,octal; 6 tns =. ND; Non-DMA Mode: A single bit of a command code of the Specify instuction. ND contols the opeating mode of the Contolle. hen ND =, the non-dma mode is selected; when ND =, the DMA mode is selected. USfUS; Unit Select: Two bits of a command code of evey instuction (except Specify) that ae used to select a dive. US USO Dive Selected 2 3 E

16 E4.3 Instuction Desciptions The following listing descibes the instuctions and the ode in which the byte and bit paametes of Pats E4. and E4.2 must be witten to and ead fom the Multi-Pupose Stack (QBMS) to execute the instuctions. (Note: An 'x' bit is a 'don't cae' state.) E4.3. ead Data Instuction Nine bytes ae witten to OEMS to pefom the ead Data instuction. Afte the instuction has been issued, the FDC loads the head (if it is in the unloaded state), waits the specified head settling time (defined in the Specify instuction) and begins eading ID Addess Maks & ID Fields. hen the cuent secto numbe (), stoed in an ID egiste compaes with the secto numbe ead off the diskette tack, the FDC will output data (fom the data field), byte-by-byte, to the Q-bus. Afte the cuent-secto data field is ead, the Secto Numbe is incemented, by, and the data fom the next secto is ead and outputted to the Q-bus. This continuous-ead is a 'Multi-Secto ead Opeation'. The ead Data instuction may be teminated by the FDC eaching DMA Teminal Count (TO, (fom QBTC). hen the FDC eaches TC, the FDC will stop outputting data to the Q-bus, but will continue to ead data fom the cuent secto, check the CC bytes, and then teminate the ead Data instuction at the end of the cuent secto. The 'Multi-Tack' function (MT bit) allows the FDC to ead data fom both tacks of a cylinde. Fo any cylinde, data will be tansfeed stating at Secto, Side and completing at Secto L (last secto) of Side. hen N =, then DTL defines the data length which the FDC must teat as a secto. If DTL is smalle than the actual data length in a secto, the data beyond DTL is not sent to the Q-bus. The FDC will ead the emaining secto data to pefom the CC check, and, depending on the manne of instuction temination, may pefom a "Multi-Secto* ead opeation. hen N is non-zeo, DTL has no significance, and must be set to FF,hex o 377,octal. At the completion of the ead Data (o ite Data) instuction, a head is not unloaded until a 6 ms inteval has elapsed. If the CPU issues anothe instuction befoe the head unloads, then the delay caused by the Head Load Time (HLT) inteval may be eliminated fo subsequent ead/wite opeations. If the Contolle detects the diskette Index Hole twice, without finding the coect secto (as defined by ), then the FDC will set the ND flag in ST, and teminate the instuction. STO bits 7 4 6, (Inteupt Code bits), will be toggled to and, espectively, to flag an abnomal temination. El 2

17 it eekdinb *$?. ID and Data fields in each secto, the FDC checks the CC bytes. If an incoect CC in the ID Field is detected, the DE (Data Eo) flag in ST will be set. If an incoect CC is ST2 «?o and 5 «. " the DE S%?ata flag of Field» ST will the DD both (Data be set. Eo In in both Data cases, Field) the flag 5lad in Data instuction will be teminated. #4 FD e?ds a deleted Data Addess Mak (DDAM) off the diskette and SK =, the Contol Mak (CM) flag in ST2 will be set, and the '!!i?a4nstiuckon^n be te^inated afte the secto data is ead. If SK =, the FDC will skip ove the secto with the Deleted Data Addess Mak and ead the next secto. The CC bytes in the deleted data field ae not checked when SK. «o?b 2ata ta"ffes between the FDC and the Q-bus, the FDC must be seviced evey 27 micoseconds in the FM mode, and evey 3 micoseconds in the MFM mode, o the FDC will set the Ove un (O) flag in ST, and teminate the ead Data instuction. If a ead (o a ite) instuction is teminated, the Secto ID infomation, duing the esult phase, will be dependent upon the till6 H^*/'7 bit and ET *>yte loaded duing the Command phase. The ^fomation, (C, H,, N), at temination, is shosn in 7m»i?s J? auu7l f data tnat can be tansfeed depends upon MT (Multi-Tack), MF (Mode), and K (Numbe of Bytes/Secto). Table 2 lists the tansfe capacity. EAD DATA Phase / FDC Data egi ste Bits emaks Command V MT MF X SK X X X Command codes HD US USO V V V V V w w -C - Secto ID H-... codes pio p to instuction - -N... execution. EOT GPL - DTL Execution esult Data tansfe fom a dive to the Q-bus. STO Status info ST... mation afte -ST execution. -C Secto ID --H codes afte --. instuction N - execution. E3

18 E4.3.2 ead Deleted Data Instuction This instuction is the same as the ead Data instuction, except that when the FDC detects a Data Addess Mak, at the beginning of a Data Field (and SK ), it will ead all the data in the secto, set the CM (Contol Mak) flag of ST2, and teminate the instuction. If SK :, then the FDC skips ove the secto with the Data Addess Mak and eads the next secto. EAD DELETED DATA Phase / FDC Data egiste Bits 5 emaks Command MT x MF x SK x x x HD US USO Command codes w K C Secto ID ----H codes pio ---. to instuction... n execution. - EOT GPL DTL Execution Data tansfe fo. a dive to the Q-bus. esult STO Status info- ST mation afte -ST2 execution. C Secto ID H codes afte instuction -N... execution. Eli*

19 E4.3.3 ite Data Instuction Nine bytes ae witten to the FDC Data egiste to pefom the ite ( Data instuction. Afte the instuction has been issued, the FDC loads the head (if it is in the unloaded state), waits the specified head settling time (defined in the Specify instuction), and begins eading ID fields. hen the cuent secto numbe (), stoed in an ID egiste, compaes with the secto numbe ead off the diskette tack, the FDC will tansfe data fom the Q-bus to the diskette dive. Afte witing data into the cuent secto, the Secto numbe is incemented, by, and the next data field is witten onto the tack. The FDC continues this 'Multi-Secto ite Opeation until a DMA Teminal Count (TC) is eached (fom QBTC). hen.the DMA TC occus, the FDC continues to wite into the cuent secto; if the DMA TC is eached while a data field is being witten, the FDC will wite zeoes into the emainde of the field. The FDC eads the ID field of each secto and checks the CC bytes. If an incoect CC is detected, the FDC will set the Data Eo (DE) flag of ST, and teminate the ite Data instuction. If the FDC ties to access a secto beyond the final secto (as configued by SC duing a Fomat a Tack instuction), of a cylinde, the EN (End of Cylinde) flag bit, of ST, will be set. In the ite Data instuction, data tansfes between the FDC and the -^ Q-bus must occu evey 3 micoseconds in the FM mode, and evey 5 ( micoseconds in the MFM mode, o the FDC will set the Ove un (O) flag in ST, and teminate the instuction. STO bits (Inteupt Code bits) will also be toggled to and, espectively, to flag an abnomal temination. The ite Data instuction opeates in much the same manne as the ead Data instuction. The following items ae the same:. Secto ID Infomation when the CPU teminates an instuction. (efe to Table El.) 2. Tansfe Capacity (efe to Table E2). 3. Definition of DTL when N is and is not zeo. 4. Head Load and Unload Time intevals. 5. ND (No Data) flag bit of ST. E5

20 ITE DATA Phase /K FDC Data egiste Bits 6 5 emaks Command MT MF Command codes w x x x x x HD US USO C- Secto ID * H codes pio V" to instuction jj execution. EOT GPL- DTL Execution Data tansfe fom the Q-bus to a dive. esult I STO Status info ST mation afte ST2 execution. c Secto ID K codes afte «_ instuction ti execution. E4.3.4 ite Deleted Data Instuction This instuction is the same as the ite Data instuction, except that a Deleted Data Addess Mak is witten at the beginning of the Data Field, instead of the nomal Data Addess Mak. ITE DELETED DATA Phase / FDC Data egiste Bits emaks Command MT MF Command codes x x x x x HD US USO C Secto ID V? - -H codes pio to instuction n execution. EOT V GPL Execution Data tansfe fom the Q-bus to a dive. esult STO Status info- ST mation afte ST2 - execution. C Secto ID K codes afte instuction - -_- _k execution. E6

21 E4.3.5 ead A Tack Instuction is simila t the ead Data instuction, except that lljz ^«ous ead opeation, whee the entie data field, n * sectos, is ead. Afte the Index Hole is detected JC staj\ts fading all the data fields on the tack, as etected' hill?pukv?lcksf f d?ta* If the FDC finds an «o in the ID o Jlil. ^?n ^t/.contlnues to ead data fom the tack. The FDC compaes the ID infomation ead fom each secto with a value stoed bit Sf of ST?eSJ?ltehi will be set. luthtmulti-tack V^UtS d and not match' skip opeations the ND (NoaeData) not flag allowed with the ead A Tack instuction. This instuction teminates when the EOT numbe of sectos have been Tti^6?\C d2es 5Ot find an ID Addess Mak on the dlsketu 2J5 H lemhaf^bjfn detected, fo the second time, then the Addess Mak) flag bit in ST will be set, and the w?nai «i [! "I?V!nin!ted- ST bits 7 &6 inteupt Code bits) will also be toggled to &, espectively. EAD A TACK Phase / FDC Data egiste Eits H 3 2 emaks Command MF SK x x x x x HD US USO Command codes w V w V V. V v: C Secto ID " H -_ codes pio -.. to instuction N execution. EOT GPL DTL Execution esult Data tansfe fom a dive to the Q-bus. The FDC eads all data fields fom the Index Hole to EOT. STO Status info- ST mation alte -ST execution. C Secto ID H... codes afte instuction N execution. E7

22 E4.3.6 ead ID Instuction The ead ID instuction is used to give the pesent position of the ead/wite head. The FDC stoes the values fom the fist ID Field it is able to ead. If no pope ID.Addess Mak is found on the diskette, befoe the Index Hole is encounteed fo the second time then the MA (Missing Addess Mak) flag bit in ST is% set; if no date is found, the ND (No Data) flag bit in ST is also set. The instuction is then teminated, and STO bits 7 & 6 (Inteupt Code bits), ae also toggled to &, espectively, to flag an abnomal temination. EAD ID Phase / FDC Data egiste Bits emaks Command K x MF x SK x x x HD US USO Command codes Execution The fist coect fom the cylinde Data egiste. ID infomation ead is stoed in the FDC esult STO Status info- ST mation afte ST2 execution.._c Secto ID K codes afte _ instuction -N execution. E8

23 E4.3.7 Fomat A Tack Instuction /f?*n Iht TnHpvtHnnft>UCiln allows an entie tack to be fomatted. Afte tin Hole is detected, fomat data is witten on the tack: SS/d f aksi ID Fields and Data Pattens, fo single o ^ y*e\?dinf' ae Stoed- The Paticula fomat to be hvltt/* \ T^??^ by the values Pogammed into: N (no. of bytes/secto), SC (sectos/cylinde), GPL (gap length of Post-ID a " h8tan^^ a"d» (D«t. Patten)'byte. The* Ja?aFieldifilled buo»«s fs^fh fnkdefiitlon* The ID Field fo «* secto is bv III n?;b??j that is' fou equests, pe secto, ae made othffc/ /: C (Cylinde No.), H (Keed No.), (Secto No.) and thij ftl VI i}c:emente6 by o^, afte each secto is fomatted, so hi»i5, if «8iste contains a value of when it is ead, duing FDC 2lEihP?!8e; JhlV?C!nenting 4 fomattine continues until the FDC detects the Index Hole fo the second time, and teminates the i^^ll6^6'5 ^ " S Md G?L hi f^ FOMAT A TACK /^^fe\ Phase / FDC Data egiste Bits 6 5 H 3 2 emaks Command x MF x x x X HD US USO Command codes v: K Bytes/Secto SC Sectos/Tack GPL Gap 3 D Fille Byte Execution esult The FDC fomats an entie tack. SXO Status info ST mation afte ST2 execution. C in this case, H secto ID has no N meaning. E9

24 E4.3.8 Scan Instuctions The Scan instuctions allow data that is being ead fom a diskette '? be compaed against data that is on the Q-bus (in the DMA mode) The FDC compaes the data on a byte-by-byte basis, and looks fo a secto that meets the equiement of the Scan instuction (i.e. Date Equal; Data Equal o Low; Data Equal o High). One's complement aithmetic is used fo the compaison (FF, hex = lagest numbe- - smallest numbe). Afte a whole secto of data is compaed, if the?,ndijions ae not met> the secto numbe () is incemented by STP IH STP etuned to ), and the Scan opeation is continued. The opeation continues until one of the following events occu: the conditions fo Scan (Equal, Low o High) ae met, the last secto on the tack is eached (EOT), o the DMA TC (Teminal Count) is eached. If the conditions fo Scan ae met, the FDC will set the SH (Scan Equal Hit) flag bit of ST2, and teminate the instuction. If the conditions fo Scan ae not met, between the stating secto (as specified by JO and the last secto (as specified by EOT), then the FDC will set the SN (Scan Not Satisfied) flag bit of ST2, and teminate the instuction. If the DMA TC is eached duing the Scan opeation, the FDC will complete the compaison of the cuent byte, and then teminate the instuction. Table E4 lists the states of SH and SN unde vaious conditions of Scan. If the FDC encountes a Deleted Data Addess Mak on one of the ^, sectos, and SK =, then this secto will be egaded as the last v secto on the cylinde; the FDC will set the CM (Contol Mak) flag bit of ST2, and teminate the instuction. If SK = when the Deleted Data Addess Mak is encounteed, the FDC will skip ove that secto and ead the next secto; the FDC will also set the CM bit of ST2 to indicate that a Deleted Data Addess Mak had been encounteed. hen eithe the STP (scan contiguous sectos = ; scan altenate sectos = 2) o the MT (access both tacks of a cylinde = ) vaiables ae pogammed, it is necessay to emembe that the last secto on the tack must be ead. Fo example, if STP 2, and MT =, and if the sectos ae numbeed sequentially though 26, and the Scan instuction is stated at Secto 2, then the following will occu: Sectos 2, 23 and 25 will be ead, Secto 26, (the last secto), will be skipped and the Index Hole will be encounteed, theeby teminating the instuction, abnomally. If EOT had been set to 25, (instead of 26), o if the Scan had stated at Secto 2, instead of 2, the instuction would have teminated nomally. Duing a Scan instuction, data is tansmitted fom the Q-bus and the diskette and compaed in the FDC. The data bytes must aive at the FDC within 27 micoseconds (fo FM mode) o 3 micoseconds (fo MFM mode), o the O (Ove un) flag bit of ST will be set and the instuction will teminate abnomally (the Inteupt Code bits 7 & 6, of STO will be toggled to 4, espectively). E2

25 SCAN EQUAL Phase /K FDC Data egiste Bits emaks Command MT x MF SK x x HD US USO Command codes K V w w w C Secto ID " K codes pio to instuction N execution. ET GPL DTL Execution esult Phase Command Execution esult / w w V V V V w Dive and Q-bus data is compaed. ST Status info- ST nation afte ST execution. c Secto ID H codes afte instuction K execution. SCAN LO O EQUAL FDC Data egiste Bits emaks 7 6 5^32 MT MF SK Command codes * x x x x HD US USO c Secto ID -K codes pio _---_..... to instuction N execution. EOT GPL DTL Dive and Q-bus data is compaed. STO- Status info ST--... mation afte ST2 execution. C Secto ID -H codes afte instuction. -K._ execution. E2

26 SCAN HIGH O EQUAL Phase / FDC Data egiste Bits emaks 7 65 H 3 2 Command Hl MF SK Command codes x * x x x HD US USO V V v: w w w III C Secto ID ~~~ H codes pio to instuction K execution. - GPL-IIIIIIIIIIIIIII DTL Execution Dive and Q-bus data is compaed. esult fj Status info- ST mation afte ST2 execution. c Secto ID H codes afte P. instuction N execution. E22

27 E4.3.9 Seek Instuction The ead/wite heads of the dives ae moved fom cylinde to SZJ?!!*" unde conto of tne Seek instuction. The FDC compaes the PCN (Pesent Cylinde Numbe) to the N (New Cylinde Numbe), and if thee is a diffeence, steps to a new cylinde. The ate at which steps occu is contolled by ST (Stepping ate Time), in the Specify instuction. Afte each step, N is Sal *J? A?!!en.!i = fcn' the SE (Seek End) "ag bit of STC set, and the instuction will be teminated. 5n }!!B H!e ommand Pnase of Seek, the FDC is in the FDC Busy state: duing the Execution phase, it is in the Non-Busy state. Anothe Seek instuction can be issued while the FDC is in the Non-Busy state: in this manne, paallel Seek opeations can be pefomed on up to H dives, simultaneously.. pf.!«f^lve JS in 8 N2t-eady state at the beginning of the Seek Execution phase, o duing the Seek opeation, the N (Not eady) t!bt i?t? ^"i be Set> and the instuction will be teminated. The Inteupt Code bits, 7 & 6, of STO, will be toggled to &, espectively. ' SEEK Phase / FDC Data egiste Bits 6 5^32 emaks Command V x x x x N- x HD US USO Command codes Execution Head is positioned ove the pope cylinde on the diskette. Note: Because Seek does not have a esult phase, a Sense Inteupt Status instuction must always be pefomed afte a Seek instuction, to effectively teminate Seek. E23

28 E4.3. ecalibate Instuction The function of this instuction is to etact the ead/wite head of a dive to the Tack position. The FDC cleas the contents of the PCN (Pesent Cylinde Numbe) counte, and checks the status of a Tack signal fom the dive. As long as this Tack signal is low, Steps ae issued to move the head. hen the Tack signal goes high, (indicating that the head is at Tack ), the "BE (Seek End) flag bit in ST will be set and the instuction teminated. If the Tack signal is still low afte 77 Steps have been issued, the FDC will set the SE and EC (Equipment Check) flag bits of STO, and teminate the instuction. The Inteupt Code bits of STO. bits 7 & 6, will be toggled to &, espectively. The ability to do ovelapping ecalibate instuctions to multiple dives, and the loss of a dive eady signal, (as descibed in the Seek instuction), also applies to the ecalibate instuction. ECALIBATE Phase / FDC Data egiste Bits 6 5 H 3 2 emaks Command x x x x x US USO Command codes Execution Head etacted to Tack. Note: Because ecalibate does not have a esult phase, a Sense Inteupt Status instuction must be pefomed afte a ecalibate instuction to effectively teminate ecalibate. E4.3. Sense Dive Status Instuction This instuction can be used to obtain the status of the dives. ST3 contains the dive Status infomation. SENSE DIVE STATUS Phase / FDC Data egiste Bits 6 emaks Command esult Command codes x x x x HD US USO ST3- Dive status E2U

29 E4.3.2 Sense Inteupt Status Instuction An inteupt signal is geneated, by the FDC, fo one of the following easons:. Upon enteing the esult Phase of the following instuctions: A. ead Data B. ead a Tack C. ead ID D. ead Deleted Data E. ite Data F. Fomat a Tack G. ite Deleted Data H. Scan (High, Low o Equal) 2. A dive changes its eady state. 3. The end of a Seek o. ecalibate instuction. caused by occu duing nomal command opeations and ae. discened. Inteupts caused by 2 & 3, howeve can be ffiis-fstjs^fj^jj?!.":!.» t *% -"* *«t» SiS. hen oi the inteupt will be *j..ij.^u, vie uiis Oj o ana y o STO, as follows: (isujupt "d\> islh L> f n? eady line changed state, eithe polaity. " ] Nomal temination of Seek o ecalibate. ' Abnomal temination of Seek o ecalibate. Nt6: nh»^?fhoe?6ek -.tlie ecalib»"ate instuctions have a esult phase; theefoe, it is mandatoy that the Sense Inteupt Status instuction be used, immediately aftewads, to effectively teminate Seek o ecalibate, and to povide head position veification. SENSE INTEUPT STATUS Phase /w FDC Data egiste Bits emaks Command Command code esult STO FDC status at the end of seekopeation. E25

30 4.3.3 Specify Instuction w" S^cl y i"stuction sets the initial values of thee times in the FDC: HLT (Head Load Time), HUT (Head Unload Time), and ST (Step ate Time). This instuction also detemines the Contolle opeating mode via the ND (Non-DMA) bit. These time and contol vaiables ae descibed in Pats E-J. 4 EU.2 of this document. SPECIFY Phase /w FDC Data egiste Bits emaks Command V Command codes V < ST > < HUT > < HLT > ND E4.i Invalid Opeation If an invalid instuction (one not descibed in Pat E4.3) is sent to the FDC, the FDC will teminate the instuction afte Inteupt Code bits 7 4 6, of STO, ae toggled to 4, espectively. Bit 7 (QBMS 5tatus) and bit 6 (Data Tansfe Diection) of OEMS will both be set, indicating that the FDC is in a esult phase and that the contents of STO must be ead. hen STO is ead, it will be found to contain ^ (hex), indicating that an invalid instuction was issued. A Sense Inteupt instuction must be sent afte a Seek o ecalibate instuction, o else the FDC will intepet the next instuction to be an invalid one. INVALID Phase / FDC Data egiste Bits emaks Command Invalid Codes- esult STO = 8,hex 2,octal E26

31 V.I EOT Final Secto Tansfeed ID Info g esult Phase H N 32 7 Secto to 25 Side Secto to 4 Side Secto to 7 Side o 32 7 Secto 26, Secto 5, Secto 8, Side Side Side C+ C + C+ s 32 7 Secto to 25 Side Secto to 4 Side Secto to 7 # Side Secto 26, Secto 5, Secto 8, Side Side Side C+ C+ C+ = = = 32 7 Secto to 25 Side Secto to 4 Side Secto to 7 i Side Secto 26, Side Secto 5, Side Secto 8, Side LSB LSB LSB 32 7 Secto to 25 Side Secto to 4 Side Secto to 7 Side Secto 26, Secto 5, Secto 8, Side Side Side C+ C+ C+ LSB LSB LSB o Note : s No Change; the sane value as was loaded duing the Command Phase. Note 2: LSB (Least Significant Bit); the LSB of H is complemented. Note 3: EOT is listed in octal; Secto is listed in decimal. TABLE El. ID Infomation hen The CPU Teminates An Instuction E27

32 MF N Maximum Tansfe Capacity Final Secto ead. (Bytes/Secto)x(No. of Sectos) fom Diskette (28)x(26) = 3, Side o (256)x(26) = 6, # Side (28)x(52) = 6, Side (256)x(52) =332 (256)x(5) = 3,84 5 Side o 2 (52)x(5) = 7I68 5 Side (256)x(3) = 7,68 5 % Side 2 (52)x(3) =5,36 2 (52)x(8) = 4,96 8 Side o 3 (24)x(8) = 8,92 8 Side 2 (52)x(6) = 8,92 8 Side 3 (24)x(6) =6384 Table E2. Tansfe Capacity N SC GPL() GPL(2) Kode Secto Size Fomat (Bytes/Secto) C* SJ FK 28 IBK Diskette FK 256 IBK Diskette FK x x FK, x x FK 2,4 8 5 x x FK 4, MFK 256 IBM Diskette 2D MFM MFM,24 IBM Diskette 2D 4 4 x x MFM 2, x x MFM 4,96 6 x x MFK 8,92 Note: The GPL() values ae suggested fo Bead and ite instuctions to avoid splice points between the Data Field and ID Field of contiguous sectos. The GPL(2) values ae suggested fo the Fomat instuction. The N, SC and GPL values ae in hexadecimal. The x values ae to be detemined by the use. SC and GPL ae listed in octal. Table E3. Fomatting Vaiables E2 8

33 Command Status egiste 2 SN = Bit 2, SH = Bit 3 Comments Scan Equal Data(Dive)=Data(Q-bus) Data(Dive)not=Data(Q-bus) Scan Low o Equal Data(Dive)=Data(Q-bus) Data(Dive)<Data(Q-bus) Data(Dive)>Data(Q-bus) Scan High o Equal Data(Dive)=Data(Q-bus) Data(Dive)>Data(Q-bus) Data(Dive)<Data(Q-bus) Table E4. SH & SN Status Bits BIT 7, BIT 6 : INTEUPT CODE (IC). Bit Bit 7 6 = Nomal temination of instuction (NT). Instuction was popely executed and completed. Bit Bit 7 6 = Abnomal temination of instuction (AT). Execution was stated, but not sucessfully completed. Bit Bit 7 6 = = Invalid instuction issued (IC). Instuction was issued, but neve stated. Bit Bit 7 6 Abnomal temination' due to state change of a dive eady signal, duing instuction execution. BIT 5 : SEEK END (SE). hen the FDC completes the SEEK instuction, this flag is set (). BIT EQUIPMENT CHECK (EC). If the dive fails to each Tack afte 77 Steps (duing the ecalibate instuction), then this flag will be set (). BIT 3 : NOT EADY (N). hen a dive is in a Not-eady state and a ead/wite instuction is issued, this flag will be set. If a ead/wite instuction is issued to Side of a single-sided dive, this flag will be set. Table E5. Status egiste Desciption E29

34 BIT 2 : HEAD ADDESS (HD). BIT : UNIT SELECT (USD. BIT : UNIT SELECT (USO). This flag is used to indicate the state of a head when an inteupt occus. hen set. the head is down. These bits indicate the selected dive when an inteupt occus: Bit Bit Dive Selected 2 3 Table E5. (Cont.) Status egiste Desciption BIT 7 : END OF CYLINDE (EN). hen the FDC ties to access a secto beyond the final secto of a cylinde, this bit will be set. BIT 6 : Not used; always low (). BIT 5 : DATA EO (DE). BIT U : OVE UN (O). hen the FDC detects a CC eo in eithe an ID field o a Data field, this flag is set. If the FDC is not seviced within a cetain time, duing data tansfes, this flag is set. efe to the ead and ite Data and the Scan instuction desciptions fo the time intevals. BIT 3 : Not used, always low (). BIT 2 : NO DATA (ND). Duing the execution of a EAD DATA, ITE DELETED DATA o SCAN instuction, if the FDC cannot find the Secto specified in an ID egiste, this flag will be set. Duing the execution of a EAD ID instuction, if /*s the FDC cannot ead the ID field without an eo, ( this flag will be set. Table E6. Status egiste Desciption E3

35 BIT : NOT ITABLE (N). BIT : MISSING ADDESS MAK (MA) TableJ6:_(Cont.)Jtatus egiste Desciption BIT 7 ; Not used; always low. p BIT 6 : CONTOL MAK (CM). BIT 5 : DATA EO IN DATA FIELD (DD). BIT i : ONG CYLINDE (C). BIT 3 : SCAN EQUAL HIT (SH). BIT 2 : SCAN NOT SATISFIED (SN). a. Table E7. Status egiste 2 Desciption E3

36 BIT : BAD CYLINDE (BC). f^ hen the value of C (Cylinde Numbe) witten on th* tack is FF,hex (377,octal), this flag will be set Also, when the C (Cylinde Numbe) value witten o the tack diffes fom the value stoed in an ID ' egiste, this flag will be set. hen BC is set, nd of ST will also be set. - ' BIT : MISSING ADDESS MAK IN DATA FIELD (MD). If the FDC cannot ead a Data Addess Mak o Deleted Data Addess Mak, this flag will be set. Table E7. (Cont.) Status egiste 2 Descipti on 7 : Not used. Always. BIT 6 : ITE POTECTED (P). BIT 5 : EADY (Y). BIT U : TACK (TO). BIT 3 : TO SIDE (TS). BIT 2 : HEAD ADDESS (HD). BIT : UNIT SELECT (USD. BIT : UNIT SELECT (USO). JpK This bit indicates the ite Potected state of a dive. ite Potected. This bit indicates the eady state of a dive eady. This bit indicates whethe a dive head is positioned ove Tack. Tack =. This bit indicates if a two-headed dive AND a twosided diskette ae in use. Two-Sided s. This bit indicates the side selected fo a twoheaded dive. Side Selected =. These two bits indicate the dive unit selected. US USO DIVE SELECTED 2 3 Table E8. Status egiste 3 Desciption E32

37 E5. Boot OM f^ i^t^.fs"^?!!.? 5?M,b«tsiap Pceam. The function of the pocai tansfe is completed. LST_n tpu «~~<._!i ]:': ;.*. n tpe The OM bootstap begins at location 73 '''S3""55 8P'CJ!!nd *"«6?8i intelih^ne executed, o the system eset (boot switch?h.ph% I* Cycled' CPU conto is tansfeed to The bootstap pogam will then:. Suspend CPU inteupts. 2. Ceate a tempoay stack beginning at location 7, octal. 3. elocate itself, beginning at, octal. ne b? ^tap pogams the FDC to ead Secto 7, w \ lt :. f the diskette in Unit. At byte locations 2 diskette attibute identifies ae stoed, as pe the IBM at;?n- Ah6n ih locations have been examined, ans the attibutes detemined, the FDC is appopiately pogammed. H^t PC a!?d the disk dive ae capable of suppoting these attibutes, logical block, of the system disk, is efd info et[eso?o cocuedetihg *this ^ansfe' ^ bootstap will lltlm ltlll Sii? Zt L^Ja?lTe: P^ "ss- If the pescibed numbe of eties will not complete the tansfe, the CPU will suspend opeation by executing a banch-to-self instuction At this uction At thi secueneh![n sequence S![ being pocessed il "S^l" at the the time m Oy of ^cation the eo. o?*t5e?*5 CPU FDC S^SS^ lti f Si'"?.'?!!eJ?ai spefial attibutes of the OM bootstap pogam. One is that the bootstap pogam will wait until dive unit di vpefffs Vl meanin& that a diskette need not be inseted in the?sl?ilv?e begi9?lns of the boot pocess. The pogam will wait indefinitely, until a diskette is inseted and the dive doo closed Anothe featue is that the OM bootstap contain! a eadonly- Aeation ^\ f ^^ ^V?* beakp *"t (BPT) instuction.!«-:?? <?f the bootstap, and its elocation, will set up locations 4 and 6, octal, to utilize the eadlonly-handle. The agument sequence is as follows: = Physical Tack No. (-76, decimal) unning wod count 2 s unning buffe addess 3 (high byte) = Head No. (Always fo single-sided dives) 3 (low byte) = Secto No. (-26, decimal, fo single-density) (-5, decimal, fo double-density) This outine may be used fo diagnostic ead, o tests. E33

38 J VAIABLE DENSITY FLOPPY DISK CONTOLLE (FDC) BOOT OM CODE CHAACTEISTICS SIZE AVAILABLE (52.) BYTES, 4 (256.) ODS LOCATION 73 DEVICE CHKSUM VECTO (776 ELATIVE) (774 ELATIVE) ID VALUES ; CONTOLLE ADDESSES QBCS =7 QBMS =BCS+2 OBDC =72 OBTC =QBDC+2 QBBA =QBDC ,73766,7377,73772 (764,766,77,772 ELATIVE) ;FDC CONTOL + STATUS EGISTE ;FDC DATA EGISTE ;DMA CONTOLLE STATUS EGISTE ;DMA OD COUNT EGISTE ;DMA ADDESS EGISTE ; FDC COMMAND VALUES SPECFI =3 ECAL =7 EED =6 SEEK =7 SENSAT = ; DMA COMMAND VALUES DMAED =4 DMAENB = 2 ;SPECIFY COMMAND ;E-CAL COMMAND ;EAD COMMAND ;SEEK COMMAND ;SENSE INTEUPT STATUS COMMAND ;DMA EAD (XFE TO MEMOY) ;DMA EAD ENABLE ; FDC DATA VALUES STEP UNHLD HLOADS DMAMOD SD DD DS.ID DD.ID SIZE SIZE2 N H2 EOT ET2 CPL GPL2 DTL DTL2 QV. QV2. V.2 V2.2 { =-6. = 7 = 8. = = = =324 =362 =64. =256. = = 2 =26. = 5. =7. = 27. =377 =377 =ET«4 =DTL*4 =ET2«4 =DTL2*4 m JGPL!N2 IGPL2 STEP ATE FO BOOT POCESS (6. X MSEC) HEAD UNLOAD TIME HEAD LOAD TIME (8. X 2 MSEC) DMA MODE SINGLE DENSITY DOUBLE DENSITY VOLUME ID FO DS VOLUME ID FO DD ODS PE SECTO SSSD ODS PE SECTO SSDD, DSDD SSSD = ((28. BYTES PE SECT)/28.)-i SSDD,DSDD = ((52. BYTES PE SECTO)/28 SSSD 26. SECTOS PE TACK SSDD,DSDD = 5. SECTOS PE TACK SSSD GAP LENGTH SSDD,DSDD GAP LENGTH SSSD DATA LENGTH SSDD,DSDD DATA LENGTH E34

39 ; OM BOOTSTAP VALUES BBPT =4 ;BPT ADDESS STACK =7 JADDESS FO TEMPOAY STACK fjload = JADDESS TO ELOCATE OM TO IN AM OMSIZ =<VECT+2-BT>/2 ;OM SIZE IN ODS Stno =?n2n ; ADDESS FO SSSD.DSSD TACK.SECTOS LAD2 = ; ADDESS FO SDDD,DSSD TACK,.SECTOS ; STAT VDC EXECUTABE OM CODE I BOOT: MTPS #3^ {DISABLE INTEUPTS #STACK,SP ;SET A TEMPOAY STACK ; BELOCATE THE OM INTO AM ; DO IT IN SUCH A AY THAT IT CAN BE LOCATED ANYHEE IN MEMOY PC,2 ;GET CUENT PC SUB #<.-BOOT>,2 ;2 = LOC (BOOT:) #BTLAD, ; = LOC (TAGET LOCATION FO OM) ; IKIT CHECK SUM ACCUMULATOS CL CL fm 5, ELOCATION + CHKSUM VEIFY LOOP «OMSIZ,O ;SET OD COUNT TO XFE ELOOP: (2)+,() ()+f3 ADD 3,^l SAB ADD SOB 3 3,5 O,ELOOP ;TEST FO ELOCATION EO B i),()+ ; LO BYTE CHECKSUM B 5,()+ ; HIGH BYTE CHECKSUM TST -() BEQ XFETO jbah IF NO XFE FAILUE B. ;IDLE AS HAD AN EO ; JUMP TO ELOCATED CODE XFETO: #BTLOAD+<BSTT-BOOT>,PC E35

40 ; STAT OF THE FUTIONAL POTION OF THE BOOTSTAP ; SET UP BPT FO EAD ONLY HANDLE *34 #BTLOAD+<QOH-BOOT>,-(SP) (SP), //BBPT ; SAVE FO FUTUE EFEEE ; USE THE "SPECIFY" COMMAND TO POGAM NEC CHIP CALL.OD XOT BTLOAD+<SPECK-BOOT> ; SEEK INTENAL TACK FO GUAANTEED E-CAL AND DIVE EADY J AUTOMATIC SENSE INTEUPT GIVEN FSEEK: DECB SENT ; CLEA ETY COUNT CALL XQT.OD BTLOAD+<SEEKT-BOOT> BCS FSEEK ; DO A "E-CAL" SO E GET IN SY 5 AUTOMATIC SENSE INTEUPT GIVEN :al: call xot v.wod btload+<ekac-boot> BCS ECAAL ; EO TY AGAIN ;EAD TACK SECTO 7 BDT57: CL BPT O #7,3 #STACK,2 SECSIZ, ;TACK ;SECTO 7 ;BUFFE ;OD COUNT = 6H. ODS ;TAP TO OH E36

41 ;DECODE VOLUME CHAACTEISTICS fsecode:.od (PC)+,5.STACK+<72.-> ; ADDESS OF CYL=O,SECT=7 BUFFE BISB B BIC AS AS BCC- BISB i EAD TACK 4(5),(5) (5),5 #7777O,5 5 5,-(SP) 5 DTS3 #DD,QEED #QV.2,QV #QV2.2,V2 #SIZE2,SECSIZ #LAD2,LOADPT SECTO 3 "O" TO MEDIA CHA BYTES TOGETHE SSSD z (SS=."O" SD=) SSDD = 362 (SS= "O" DD=36"2) DSSD = 32^ (DS=32^ "O" SD=) DSDD = 366 (DS=324 "O" DD=362) GET IT IN A EGISTE CLEA ALL HIGH BITS DIVIDE BY 2 SSSD SSDD = DSSD = 2 DSDD 3 SAVE FO FUTUE MEDIA ID TEST FO DOUBLE DENSITY ; SET NE EAD COMMAND = DD ;NEED TO ESET SOME FDC VALUES JMUST ALSO SET NE SECTO SIZE ;SET LOAD STAT ADDESS DTS3: LOADPT:.OD BPT #,O (PC)+,2 LOAD *2, JTACK JSECTO 3 ;BUFFE ADDESS ;OD COUNT = MAX SECTO SIZE X M IN ODS ;TAP TO OH ; EAD TACK SECTO 5 DTS5: #5,3 BPT jsecto 5 ;TAP TO OH ; EAD TACK SECTO 7 DTS7: BPT #7,3 jsecto 7 ;TAP TO OH ; EAD TACK SECTO DTS: CL BPT #,3 2 jsecto JEAD INTO LOC () ;TAP TO OH 37

42 SET MEDIA CKAACTESTIC ID CL ADD Hi,(),2, (SP)+,() J SET TO STOE IN LOC = ; FLOPPY CONTOLLE ID ; ADD IN MEDIA CHAACTEISTICS ; DONE SO XFE CONTOL TO THE SOFT BOOT (JKP LOC ) JLOCO: CL PC.SBTTL VDC EAD ONLY HANDLE ; THIS OH POVIDES ALL EAD CAPABILITIES EQUIED FO THE BOOT POCESS ; IT ADHEES TO THE OH CALLING SEQUEE DEFINED IN THE SOFT BOOT FO». DEC T- V3B. UCSD PASCAL VII. ; SAMPLE CALLING SEQUEE f TN,O C, BF,2 f SN,3 BPT O.TNS.CL 2,BFL ;TN = TACK ii ;C = OD COUNT ;BF = TAGET BUFFE ADDESS ;SN = (HI-BYTEHEAD, LO-BYTE=SECTO t) ;TNS = SAME VALUE AS INPUT ;CL = OD COUNT - // ODS XFEED JBFL = BUFFE ADDESS + H ODS XFEED 4,5 AE DESTOYED QOH:,-(SP) ;SAVE O AS DEFINED BY OH CONVENTION SET TACK AND SECTO B B,QTAK 3.QSECT SET HEAD $: SAB BNE CLB CLB B B 3 $ QMOD QHED 2$ 4,QMOD 3.QHED ;SET FO HEAD ;SET FO HEAD E38

43 ;SEEK THE TACK ;. AUTOMATIC SENSE INTEUPT GIVEN QSEEK: CMPB BEQ B CALL.OD O.STAK JSEE IF NEED A TACK SEEK PODMA,-ALEADY THEE, NO NEED TO SEEK O,STAK XQT BTLOAD+<SEEKT-BOOT> PODMA: SECSIZ: i $: BCS.OD CMP BLE QSEEK ;STILL HOPE, TY AGAIN SET DMA XFE COUNT * "DMA XFE TO MEMOY" SIZE 4. 4$ 4 ;FULL SECTO SIZE ;COMPAE ITH HAT AS ASKED FO JONLY TANSFE HAT AS ASKED FO ;SAV OD COUNT ASL DEC BIS i //DMAED.4 ; POGAM DMA FO EAD ^\ ^ ki I. * m.«*. * -. _ QDMA: SAB SAB SAB //QBBA.5 2,(5) 2 2,(5) 2 4 ilf(5) #DMAENB,-(5) ;CONVET TO BYTES ;DMA XFES COUNT + (ODDITY) ;SET DMA DISK EAD BITS ;DMA ADDESS EGISTE {BUFFE LO ODE ADDESS BYTE JBUFFE HI ODE ADDESS BYTE ;ESTOE ;DMA COUNT +DISK EAD ;ENABLE DMA DO THE NEC COMMAND SEQUEE TO EAD QEAD: CALL.OD XQT BTLOAD+<EADS-BOOT> BCS QEAD ;DO IT AGAIN ; CLEAN UP OPEATION 3$: (SP)+,O SUB O, ASL O ADD.2 (SP)+,O TI ;GET OD COUNT XFED JADJUST OD COUNT ;CONVET TO ADDESS ;NE BUFFE ADDESS E3 9

44 H ; XECUTE A FDC COMMAND SEQUEE CALL.OD XQT COMTBL t COMTBL IS NEC COMMAND TABLE 5,4,3 AE DESTOYED, OTHE EGISTES UNTOUCHED ETUN CAYO CAYsi NO EO EO XQT: ADD #(SP),5 #2,(SP) ;SET COMMAND TABLE ADDESS ; BUMP AOUND DATA TABLE ADDESS B SET BYTE COUNT TO XFE TSTDY: BMI B,3 (SP)+,-(SP) TSTDY FDC EADY MINUS IS A YES NOPE SO DELAY AND TY AGAIN 4$: OL BPL CL B 3 5$ i; ST.AT TEST FDC DIECTION NOT =, EO CLEA SO KILL GET ENTIE STATUS CONFUSED, ANTS TO SEND STATUS B SOB (5)+,3 3, /(QBMS 4, TSTDY E BYTE TO EGISTE TO EXPAND TO OD E COMMAND TO FDC ;LOOP UNTIL DONE CMPLT:,3 ; DELAY BEFOE TESTING U: SOB BPL (SP)+,-(SP) 3,U #QBCS,3 CMPLT ; DELAY APPOXIMATELY MICO-SEC TEST QM POSITIVE, FIX NOT EADY 7$: B BNE B BEQ TSTDY (5)+, ETN GET NUMBE OF BYTES IN NEXT COMMAND IN SEQUEl ZEO MEANS COMMAND SEQUEE DONE GET NUMBE OF BYTES IN STATUS ZEO MEANS NO STATUS BYTES TO GET STAT: 5,-(SP) SP,5 SUB #<7+>«2,5 5,-(SP) $: *QBCS,3 BMI 2$ f^ (SP)+,-(SP) t B $ 2$: OL 3 BPL 3$ SAVE COMMAND TABLE POINTE USE STACK AEA FO STATUS VALUES MAXIMUM NUMBE OF STATUS ODS IS 7 SAVE STAT OF STATUS AEA TEST IF EADY MINUS IS A YES DELAY AND TY AGAIN CHECK DIECTION EO, NO MOE STATUS E4

45 SOB ##QBMSf(5)- {STOE STATUS OD ;SEE IF MOE STATUS ODS ^ (SP)+,5 ; ESTOE STAT OF STATUS TABLE AEA ; ESTOE COMMAND TABLE POINTE CMPB BCS #77,(^) E ;TEST FO EO CONDITION J CAY SET MEANS EO ETN; ETUN EE: FE: Ifi BPL TST B (5) ETK (SP),O -(O) J IEMENT COMMAND ETY ; HEN 2 BIT SET, ETIED ENOUGH ; ADDESS OF COMMAND IN O ; DECEMENT BY 2 ; ADDESS OF STATUS IN ;N C COMMAND TABLE FOMAT.BYTE.BYTE.BYTE.BYTE N AGIM AG#N = # BYTES IN COMMAND SEQUEE.BYTE.BYTE NS TY THE COMMAND SEQUEE CAN BE ANY LENGTH THE SEQUEE IS TEMINATED BY N= = // BYTES IN STATUS ( MEANS NO STATUS) ETY COUNT (IF NS =, THEN THIS BYTE NOT EQUIED) C COMMAND SEQUEE "SPECIFY FDC CHAACTEISTICS" ;NEC COMMAND SEQUEE "SPECIFY FDC CHAACTEISTICS" SPECK:.BYTE 3.BYTE SPECFI.BYTE STEP«2!UNHLD.BYTE HLADS*2!DMAMD BYTE ; NO MOE COMMANDS BYTE ; NO STATUS BYTES ;NEC COMMAND SEQUEE "SEEK TACK" + "SENSE INTEUPT STATUS" ;NEC COMMAND SEQUEE "SEEK TACK" SEEKT:.BYTE 3.BYTE SEEK BYTE ; UNIT STAKi BYTE 5 ;NEC COMMAND SEQUEE "SENSE INTEUPT STATUS".BYTE.BYTE SENSAT ;SENSE STATUS COMMAND BYTE ; NO MOE COMMANDS BYTE 2 ; 2 BYTES OF STATUS SENT:.BYTE ; ETY COUNTE

46 ;NEC COMMAND SEQUEE ECALIEATE DISK DIVE" + " SENSE INTEUPT ;NEC COMMAND SEQUEE ECALIEATE DISK DIVE".BYTE 2.BYTE BECAL.BYTE - -UNIT ;NEC COMMAND SEQUEE "SENSE INTEUPT STATUS" D VTT BYTE.BYTE.BYTE.BYTE.BYTE n SENSAT 2 ;NEC COMMAND SEQUEE "EAD SECTO".EVEN EADS 9. OEED QMOD: ;EAD QTAK OHED: QSECT OV: CV2:.BYTE.BYTE.BYTE.BYTE.BYTE.BYTE.OD.OD.BYTE.BYTE.BYTE QV QV2 7 NO MOE COMMANDS 2 BYTES OF STATUS ETY COUNTE COMMAND IMPLIED 'SENSE INTEUPT STATUS COMMAND ;EAD COMMAND HEAD ;TACK jhead jsecto NO MOE COMMANDS 7 BYTES OF STATUS ETY COUNTE UNIT AEA ( -BOOT+76i) CTLID: CHKSUM: V CT:.OD.OD.OD.BYTE.BYTE.OD.OD.END «A ATIBS ; THESE ODS ESEVED FO ; CONTOLLE INDENTIFICATION ; EVISION ; ATTIBUTES ; CHECKSUM ; DEVICE VECTO E42

47 7. Floppy Disk Statin ftcgutt (QBCS) (ead only) 7)OO2c Mulil-Fupott Slack (QBMS) (cad/u'lit) 72t LSB MSB DMA Comol/Siatvt tglnt (OBDC) (tad/ltt) Teminal Count tgiitt (QBTC) (tad/iie) 7 i : 7,. ; '! ' ' LSB MSB J Bu* Addle** teutt (QBBA) (cid/ht) Flflue E-l Vaiable Density Disk Contolle Q-Bus Inteface egistes 72

48 FDC DATA EG. STATUS Contaln» Valid Data DATA TANSFE DIECTION Cs Q-Buk FDC = FDC QBui DIVE STATUS s Dtivt Buiy las Dive I Busy ] s DiIvt 2 Buey is Dive 3 Busy OPEATING MODE = DMA Mode = Nun-DMA Mode FDC STATUS _ lstad o ite Command in Fit»ce»» (QBCS) FJoppv Di«k Si«iui «g(ftt«only) QfiMS= )7lOO2e Secto ID. - (Top of Siack!- Si*tui Infoi.ation Tack Fomat ID o Head Motion Paamete* to 7 Byt) (.2. o 9 Bytet) o No equiementt ( Bytet) Secto ID (4 Bytfi) e No equiement! Command Code bv m^ m^ mm* a^ ^b a II o 2 Bytei) ITE DATA TANSFE EAD COMMAND PHASE» EXECUTION PHASE» ESULTS PHASE Multt-Pypoee Stack (QBMS) (ead/ite Stack) Figue E-2 QBCS. QBMS 73-

49 722, DMA EAD/ITE c Memoy ead = Memoy ite FDC Inteupt Ettblc s Im. Enabled = In. DiteUed 7 ' ' V (ite Only) i L DMA Cycle Enabled/Complete Uiie s DMA Disabled' = DMA Enabltd tad: = DMA in Piogtii = DMA Completed DMA Contol/Steut cfiutc (QBDC) (c«d U'lte) QBTC ^ \ P/O TC Memoty ttile 7 J Memoy ) Illegal ead 7 LEAST SIGNIFICANT BYTE most significant byte J P/O TC Teminal Count (TCI- N-l j«k hee Ns No. of Dtaled DMA Cycle* Teminal Count esittc (QBTC) (cad'ite) Jfc.3»4 QBBA e 76. Siatiot 2. c 57776, e Icz MOST LEAST SIGNIFICANT BYTE SIGNIFICANT BYTE But Addea» csute (QBBA) (ead/ite) Figue E-3 QBDC. QBTC. QBBA egistes 74-

50 Cylindt {T»ck O.Sldi I Tack O.SUt Ti.ci?«.&!««t)\ Ti.cl 7fc.Sld«C»!lvdei 7t F«Encoded; 26 fctciot Indti D» c i e d Hole Lm StcioilCAP 'GAP Secto Stttei 2 Stcie OS L.i. Stict PE- POST' INDEX INDEX SY CAP CAP AM lichn POS ISYiAMS' cc IGAP IDATA BYTESj ICAP FOMATTED BY THE CONTHOLLE _J SELECTED BY THE USE TO EAD O ITE TO THE DATA FIELD: ^CYLINDE No. ( to 76 ) HEAD No. ( < ) = SECTO (acaitf) Ns. «I ic l» (Slaglt Dtntliy) c is I$,o (Danklt DtMlly! >DATA BYTES/SECTO = (Slnala Damliy) '2 IDouUi Figue E-4 Dltkctlc & Tack Geomety 7&-C