device address, 6 bits, bits 0,1,2,3,4,5 command high bits, 3 bits, bits 13,14,15 op command, 4 bits, bits 9,10,11,12
| 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | meaning |
| ad | ad | ad | ad | ad | ad | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| cmb | cmd | cmd | ctrl | ctrl | ctrl | ctrl | 0 | 0 | 1 | 0 | 1 | 1 | buffer | ||||||
| ? out | ? out | trk | trk | cmd | cmd | cmd | cmd | ? in | 0 | 0 | 1 | 1 | 0 | 1 | transport | ||||
| 1 | 0 | 0 | 1 | 0 | 1 | ??? | |||||||||||||
| 0 | 0 | 0 | 1 | 1 | 1 | initialization? | |||||||||||||
| sdsc | |||||||||||||||||||
motion command structure 9 10 11, gated 8
int12
transport commands
| 11 | 10 | 9 | 8 | name |
|---|---|---|---|---|
| 0 | 0 | 0 | 0 | stop |
| 0 | 0 | 0 | 1 | rewind |
| 0 | 0 | 1 | 0 | write continuous ibg |
| 0 | 1 | 0 | 1 | fast forward |
| 0 | 1 | 1 | 1 | read a block |
| 1 | 0 | 0 | 1 | fast reverse |
| 1 | 0 | 1 | 1 | write |
| 1 | 1 | 0 | 1 | back space |
| 1 | 1 | 1 | 1 | read continuous |
buffer commands, cps-jk10 sheet 4
| 15 | 14 | 13 | id | purpose |
|---|---|---|---|---|
| 0 | 1 | 0 | 5 | send bits 9 10 11 12 to state1 register, subdecode |
| 1 | 1 | 0 | buffer swap | |
| 1 | 0 | 0 | unused? | |
| 0 | 0 | 1 | clear br0 flipflop | |
| 1 | 0 | 1 | some sort of clear buffer counter | |
| 0 | 1 | 1 | on-line buffer fill? | |
| 1 | 1 | 1 | buffer initialization |
buffer subdecode 010 something to do with the offline buffer
| value | name | pr-1c957 ref | bin | name |
|---|---|---|---|---|
| –ccc rrrr — aaaaaa | ||||
| 000013 | bstat | p.26 | 00000 0000 000 001011 | status request |
| 020013 | bclrbrf | 1c958 p.44 | 00001 0000 000 001011 | clear br |
| 042013 | bsldon | p.60 | 00010 0010 000 001011 | prepare buffer for load |
| 044013 | bsunldon | 00010 0100 000 001011 | unload | |
| 050013 | bstfon | 1c958 p.39 | 00010 1000 000 001011 | stuff |
| 060013 | bfill | 1c958 p.42 | 00011 0000 000 001011 | right align buffer contents |
| 120013 | bclrocn | 1c958 p.41 | 00101 0000 000 001011 | clear off-line counter |
| 140013 | bswb | p.60 | 00110 0000 000 001011 | swap |
| 160013 | binit | 1c958 p.37 | 00111 0000 000 001011 | |
| –??TT cccc ?- aaaaaa | ||||
| 000215 | tmstop | 1c958 p.50 | 000000 0000 10 001101 | deselect the tape transport |
| 001015 | tscrc | 1c958 p.56 | 000000 0010 00 001101 | shift crc into buffer unit |
| 002015 | tstat | p.25 | 000000 0100 00 001101 | get status |
| 002415 | tff | p.55 | 000000 0101 00 001101 | fast forward |
| 003415 | trb | p.45 | 000000 0111 00 001101 | read block |
| 006415 | tbs | p.50 | 000000 1101 00 001101 | back space |
| 007415 | trt | p.33 | 000000 1111 00 001101 | read continuous |
| 004415 | tfr | p.64 | 000000 1001 00 001101 | fast reverse |
| 005145 | twt | p.60 | 0000001010 01 100101 | |
| 100007 | sd | 1c958 p.48 | 0010000000 00 000111 | something status |
| 010007 | sst | p.42 | 0000010000 00 000111 | |
| 040007 | init | p.48 | 0001000000 00 000111 | |
some status output bit patterns can be found in https://archive.org/details/bellsystem_PR-1C958-50/page/n15