5385E scsi register usage 19871016/wjvg 0 data register (rw) 1 command register rw ...00000 imm dit chip reset rw ...00001 imm it disconnect rw ...00010 imm d t pause rw ...00011 imm i set atn rw ...00100 imm i message accepted rw ...00101 imm dit chip disabled rw ...0011. imm reserved rw ...01000 int d select w/atn rw ...01001 int d select w/o atn rw ...01010 int d reselect rw ...01011 int d diagnostic turnaround rw ...01100 int t receive command rw ...01101 int t receive data rw ...01110 int t receive message out rw ...01111 int t received unspecified info out rw ...10000 int t send status rw ...10001 int t send data rw ...10010 int t send message in rw ...10011 int t send unspecified info in rw ...10100 int i transfer info rw ...10101 int i transfer pad rw ...1rest reserved rw ..0..... reserved (must be a zero) rw .1...... single byte transfer rw 1....... dma mode 2 control register (0 after reset) rw .......1 select enable rw ......1. reselect enable rw .....1.. parity enable rw xxxxx... reserved 3 destination id rw .....111 destination id 4 auxiliary status r .......x not used r ......1. xfer counter zero r .....1.. paused r ....1... i/o r ...1.... c/d r ..1..... msg r .1...... parity error r 1....... data register full 5 id register r .....111 device id r 00000... not used 6 interrupt register r .......1 function complete r ......1. bus service r .....1.. disconnected r ....1... selected r ...1.... reselected r ..1..... (used for testability) r .1...... invalid command r x....... not used 7 source id r .....111 source id r .xxxx... not used r 1....... id valid 8 r reserved 9 r diagnostic status r .....000 successful completion r .....001 unconditional branch fail r .....010 data reg full failed r .....011 initial conditions incorrect r .....100 initial command bits incorrect r .....101 diagnostic flag failed r .....110 data turnaround failed r .....111 not used r ..001... turnaround miscompare (initial) r ..010... turnaround miscompare (final) r ..011... turnaround good parity r ..100... turnaround bad parity r .x...... not used r 1....... self-diagnostic complete a reserved b reserved c transfer counter (msb, rw) d transfer counter (2nd, rw) e transfer counter (lsb, rw) f rw reserved for testability - end