2

VMEchip2

DMAIC The DMAC interrupt counter is incremented when an interrupt is sent to the local bus interrupter. The value in this counter indicates the number of commands processed when the DMAC is operated in the command chaining mode. If interrupt count exceeds 15, the counter rolls over. This counter operates regardless of whether the DMAC interrupts are enabled. This counter is cleared when the DMAC is enabled.

DMAC Status Register

ADR/SIZ

 

 

$FFF40048 (8 bits of 32)

 

 

BIT

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

NAME

MLTO

DLBE

DLPE

DLOB

DLTO

TBL

VME

DONE

 

 

 

 

 

 

 

 

 

OPER

R

R

R

R

R

R

R

R

 

 

 

 

 

 

 

 

 

RESET

0 PS

0 PS

0 PS

0 PS

0 PS

0 PS

0 PS

0 PS

 

 

 

 

 

 

 

 

 

 

This is the DMAC status register.

 

 

 

 

 

DONE

This bit is set when the DMAC has finished executing

 

 

commands and there were no errors or the DMAC has

 

 

finished executing command because the halt bit was set.

 

 

This bit is cleared when the DMAC is enabled.

 

 

VME

When this bit is set, the DMAC received a VMEbus

 

 

BERR during a data transfer. This bit is cleared when the

 

 

DMAC is enabled.

 

 

 

 

 

TBL

When this bit is set, the DMAC received an error on the

 

 

local bus while it was reading commands from the

 

 

command packet. Additional information is provided in

 

 

bits 3 - 6 (DLTO, DLOB, DLPE, and DLBE). This bit is

 

 

cleared when the DMAC is enabled.

 

 

 

DLTO

When this bit is set, the DMAC received a TEA and the

 

 

status indicated a local bus time-out. This bit is cleared

 

 

when the DMAC is enabled.

 

 

 

2-64

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Page 142
Image 142
Motorola MVME172 manual Dmac Status Register, Done, Vme, Tbl, Dlto