beautypg.com

Chip test three (ctest3), Chip test three, Ctest3) – Avago Technologies LSI53C876E User Manual

Page 150: Register: 0x1b

background image

4-56

Registers

DACK

Data Acknowledge Status

0

This bit indicates the status of the LSI53C876 SCSI
function’s internal Data Acknowledge signal (DACK/).
When this bit is set, DACK/ is inactive. When this bit is
clear, DACK/ is active.

Register: 0x1B

Chip Test Three (CTEST3)
Read/Write

V[3:0]

Chip Revision Level

[7:4]

These bits identify the chip revision level for software
purposes. It should have the same value as the lower
nibble of the PCI

Revision ID

register.

FLF

Flush DMA FIFO

3

When this bit is set, data residing in the DMA FIFO is
transferred to memory, starting at the address in the

DMA

Next Address (DNAD)

register. The internal DMAWR

signal, controlled by the

Chip Test Five (CTEST5)

register, determines the direction of the transfer. This bit
is not self-clearing; clear it once the data is successfully
transferred by the LSI53C876 SCSI function.

Note:

Polling of FIFO flags is allowed during flush operations.

CLF

Clear DMA FIFO

2

When this bit is set, all data pointers for the DMA FIFO
are cleared. Any data in the FIFO is lost. After the
LSI53C876 SCSI function successfully clears the
appropriate FIFO pointers and registers, this bit
automatically clears.

Note:

This bit does not clear the data visible at the bottom of the
FIFO.

7

4

3

2

1

0

V[3:0]

FLF

CLF

FM

WRIE

x

x

x

x

0

0

0

0