********************************** * ×Ä 1770 ÆLOPPY ÄISK ÃONTROLLER * ********************************** * AUTOMATIC TRACK SEEK WITH VERIFY * SOFT-SECTOR FORMAT COMPATIBILITY * READ OR WRITE WITH: SINGLE OR MULTIPLE RECORDS AUTOMATIC SECTOR SEARCH ENTIRE TRACK READ OR WRITE * PROGRAMMABLE: TRACK TO TRACK STEPPING TIME HEAD SETTLING TIME HEAD ENGAGE TIME THREE-PHASE OR STEP-PLUS-DIRECTION MOTOR CONTROL DMA OR PROGRAM TRANSFERS ÃOMMUNICATING WITH THE 1770 IS ACCOMPLISHED BY ACCESSING SIX REGISTERS. ÁDDRESS BITS ÍÏÄÅ Á1 Á0 ÒÅÁÄ ×ÒÉÔÅ ------------------------------------------ 0 0 ÓTATUS REG. ÃOMMAND REG. 0 1 ÔRACK REG. ÔRACK REG. 1 0 ÓECTOR REG. ÓECTOR REG. 1 1 ÄATA REG. ÄATA REG. ×HERE Á0 AND Á1 ARE PINS THREE AND FOUR, RESPECTIVELY. ÉN THE ÃOMMODORE 1571 THE ×Ä1770 IS LOCATED AT ADDRESSES $2000 TO $2003. ÔHE COMMAND REGISTER RECOGNIZES ELEVEN COMMANDS: ÃOMMAND COMMAND WORD BITS 7 6 5 4 3 2 1 0 ------- --------------- 1. ÒESTORE 0 0 0 0 H V X Y 2. ÓEEK 0 0 0 1 H V X Y 3. ÓTEP 0 0 1 U H V X Y 4. ÓTEP IN 0 1 0 U H V X Y 5. ÓTEP OUT 0 1 1 U H V X Y 6. ÒEAD SECTOR 1 0 0 M H E 0 0 7. ×RITE SECTOR 1 0 1 M H E P A 8. ÒEAD ADDRESS 1 1 0 0 H E 0 0 9. ÒEAD TRACK 1 1 1 0 H E 0 0 10. ×RITE TRACK 1 1 1 1 H E P 0 11. ÆORCE INTERRUPT 1 1 0 1 I J K 1 WITH THE SPECIAL BITS DEFINED AS FOLLOWS: H - 0= MOTOR ON / 1= MOTOR OFF V - 0= VERIFY TRACK / 1= DON'T VERIFY X/Y - ÓTEP RATE 1770 1771 1772 0 0 6MS (166STEPS/SEC) 6MS ? 0 1 12MS (88) 6MS ? 1 0 20MS (50) 8MS ? 1 1 30MS (33) 10MS ? U - 0= DON'T / 1= DO SET TRACK REG TO TRACK IN SECTOR HEADER M - 0= READ ONE SECTOR / 1= READ SEVERAL A - 0= SET DATA MARK FOR 'SECTOR VALID' 1= SET DATA MARK FOR 'SECTOR ERASED' E - 0= NO HEAD SETTLING TIME 1= 30MS HEAD SETTLING TIME P - 0= PRECOMPENSATION ON / 1= PRECOMPENSATION OFF I - J - K - INDEX HOLE INTERRUPT ENABLE L - IMMEDIATE UNCONDITIONAL INTERRUPT COMMAND ENDS WITHOUT INTERRUPT IF I-J = 0 ÓÔÁÔÕÓ ÒÅÇÉÓÔÅÒ ÂIT 0. ÂUSY FLAG - A COMMAND IS BEING EXECUTED 1. ÄATA REQUEST/INDEX - SIGNALS THAT DATA CAN READ/WRITE FROM ÄÁÔÁ REG 2. ÌOST DATA/TRACK 00 - FOR COMMANDS 1 - 5 INDICATES HEAD ON TRACK ONE FOR OTHERS, INDICATES THAT DATA REG WAS LOST 3. ÃÒÃ ERROR - HEADER OR DATA BLOCK CHECKSUM INCORRECT 4. ÒECORD NOT FOUND - ÓPECIFIED TRACK OR SECTOR WAS NOT FOUND 5. ÓPINUP/RECORD TYPE - FOR COMMANDS 1 - 5 INDICATES SIX ROTATIONS FOR CMDS 6 - 11 BIT HOLDS 'DATA MARK' 6. ×RITE PROTECT - ×HEN WRITING INDICATES THAT WRT PROT IS ON 7. ÍOTOR ON - MOTOR STAUS 0= OFF / 1= ON ×Ä1770 ÐIN ÌAYOUT * ÐIN ÎAME ÆUNCTION --- ---- -------- 1 ÃÓ ÃHIP SELECT (LOW) 2 Ò/× 0= WRITE / 1= READ REGISTERS 3/4 Á0/1 ÒEGISTER ADDRESS LINES WHEN CS=0 5-12 Ä0-7 ÄATA BUS 13 ÍÒ ÍASTER RESET LOW 14 ÇÎÄ GROUND CONNECTION 15 ÖCC +5 ÖOLTS 16 ÓÔÅÐ ÏUTPUT FOR STEP PULSES TO THE HEAD MOTOR 17 ÄÉÒÃ ÓTEP DIRECTION 18 ÃÌË ÉNPUT FOR 8ÍHZ CLOCK 19 ÒÄ ÒEAD DATA FROM DISK (ALSO CONTAINS CLOCK) 20 ÍÏ ÍOTOR ON SWITCH 21 ×Ç ×RITE GATE =1 IF DISK IS BEING WRITTEN TO 22 ×Ä ×RITE DATA PULSES (ALONG WITH CLOCK) TO DISK 23 ÔÒ00 ÔRACK 0 INPUT 0= HEAD ON TRACK 0 / 1= NOT ON 0 24 ÉÐ ÉNDEX PULSE 25 ×ÐÒÔ ×RITE PROTECT 0= WRITE PRTOECT / 1= NOT PROTECT 26 ÄÄÅÎ ÄOUBLE DENSITY IF =0 / 1= SINGLE DENSITY * 27 ÄÒÑ ÄATA REQUEST 1= DATA REGISTER IS READY 28 ÉÎÔÒÑ ÉNTERRUPT REQUEST 1= END COMMAND * ÎOTE THAT IN THE ÃOMMODORE 1571, PINS 16,17,20,23,27, AND 28 ARE UNCONNECTED * PIN 26 IS HELD LOW (DOUBLE DENSITY) * ÉF YOU OWN A ÃOMMODORE 1581 AND FIND THAT IT CONTAINS A ×Ä1770 YOU SHOULD * SEE YOU ÃOMMODORE AUTHORIZED SERVICE CENTER ABOUT REPLACING IT WITH * A ×Ä1772 - AS FAR AS É KNOW, ÃOMMODORE IS STILL REPLACING THEM EVEN OUT * OF WARRANTY AS OF ÁPRIL 1988 ***************************************************************** ÔHIS INFORMATION IS THE COMPILATION OF SEVERAL SOURCES, INCLUDING DIRECT EXPERIMENTATION, AND IS PROVIDED WITHOUT ANY GUARANTEES OF ACCURACY OR ANY ASSUMPTION OF LIABILITY ON MY PART. ÇÔË ***************************************************************** ÃOMMODORE 1571 AND 1581 ARE TRADEMARKS OR REGISTERED TRADEMARKS OF ÃOMMODORE ÉNTERNATIONAL ÌTD. ×Ä1770, 1771, AND 1772 ARE TRADEMARKS OF ×ESTERN ÄIGITAL ÃORP. 3218 ÒEDHILL ÁVENUE ÎEWPORT ÂEACH, ÃÁ 92663 (714) 557-3550 Ô×Ø: (910) 595-1139