Motorola MVME1X7P manual Dmac Local Bus Address Counter

Models: MVME1X7P

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LCSR Programming Model

VMEbus address modifier bits 2-5, and address modifier bits 0 and 1 are provided by the DMAC to indicate a block transfer. Block transfer mode should not be set in the address modifier codes. The special block transfer bits should be set to enable block transfers. If non-block cycles are required to reach a 32- or 64-bit boundary, bits 0 and 1 are used during these cycles.

BLK

These bits control the block transfer modes of the DMAC:

 

0

Block transfers disabled

 

1

The DMAC executes D32 block transfer cycles

 

 

on the VMEbus. In block transfer mode, the

 

 

DMAC may execute byte and two-byte cycles

 

 

at the beginning and ending of a transfer in

 

 

non-block transfer mode. If the D16 bit is set,

 

 

the DMAC executes D16 block transfers.

 

2

Block transfers disabled

 

3

The DMAC executes D64 block transfer cycles

 

 

on the VMEbus. In block transfer mode, the

 

 

DMAC may execute byte, two-byte and four-byte

cycles at the beginning and ending of a transfer in non-block transfer mode. If the D16 bit is set, the DMAC executes D16 block transfers.

DMAC Local Bus Address Counter

ADR/SIZ

 

$FFF40038 (32 bits)

 

 

 

 

 

BIT

31

. . .

0

 

 

 

 

NAME

 

DMAC Local Bus Address Counter

 

 

 

 

 

OPER

 

R/W

 

 

 

 

 

RESET

 

0 PS

 

 

 

 

 

In direct mode, this counter is programmed with the starting address of the data in local bus memory.

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Page 149
Image 149
Motorola MVME1X7P manual Dmac Local Bus Address Counter