Programming Model

SCSI Error Status Register

ADR/SIZ

 

 

 

$FFF4202C (8 bits)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIT

31

30

29

 

28

27

 

26

25

24

 

 

 

 

 

 

 

 

 

 

 

NAME

 

 

 

 

 

PRTY

 

EXT

LTO

SCLR

 

 

 

 

 

 

 

 

 

 

 

OPER

R

R

R

 

R

R

 

R

R

R

 

 

 

 

 

 

 

 

 

 

 

RESET

0

0

0

 

0

0 PL

 

0 PL

0 PL

0 PL

 

 

 

 

 

 

 

 

 

 

 

SCLR Writing a 1 to this bit clears bits LTO, EXT, and PRTY. Reading this bit always yields 0.

LTO, EXT, PRTY

3

These bits indicate the status of the last local bus error condition encountered by the SCSI processor while performing DMA accesses to the local bus. A local bus error condition is flagged by the assertion of TEA*. When the SCSI processor receives TEA*, if the source of the error is local time-out, then LTO is set and EXT and PRTY are cleared. If the source of the TEA* is due to an error in going to the VMEbus, then EXT is set and the other two status bits are cleared. If the source of the error is DRAM parity check error, then PRTY is set and the other two status bits are cleared. If the source of the error is none of the above conditions, then all three bits are cleared. Writing a 1 to bit 24 (SCLR) also clears all three bits.

General Purpose Inputs Register

The contents of a PAL and the state of an 8-position jumper block are translated to bit settings of the General Purpose Inputs Register, Version Register and DRAM/SRAM Options Register when the MC2 chip is reset. These registers are read only. Writes to these registers are terminated without exception but do not change their contents.

http://www.mcg.mot.com/literature

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Motorola MVME172 manual Scsi Error Status Register, General Purpose Inputs Register