AM53C94JC datasheet(28/63 Pages) AMD

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P R E L I M I N A R Y

AMD

Am53C94/Am53C96

Control Register One (08H) Read/Write

Control Register One

CNTLREG1

Address: 08H

Type: Read/Write

76543

210

ETM

DISR

PTE

PERE

STE

CID2

CID1

CID0

0000

Disable Interrupt on SCSI Reset

Parity Test Enable

Parity Error Reporting Enable

Self Test Enable

Chip ID 2:0

Extended Timing Mode

16506C-28

The Control Register 1 (CNTLREG1) sets up the device

with various operating parameters.

CNTLREG1 – Bit 7 – ETM – Extended Timing Mode

The ETM bit is set if an extra clock period is required be-

tween the data being driven on the bus and the

REQ or

ACK being asserted. This is some times necessary in

high capacitive loading environments. The ETM bit is re-

set to zero by a hard or soft reset.

CNTLREG1 – Bit 6 – DISR – Disable Interrupt on

SCSI Reset

The DISR bit masks the reporting of the SCSI reset.

When the DISR bit is set and a SCSI reset is asserted,

the device will disconnect from the SCSI bus and remain

idle without interrupting the host processor. When the

DISR bit is reset and a SCSI reset is asserted the device

will respond by interrupting the host processor. The

DISR bit is reset to zero by a hard or soft reset.

CNTLREG1 – Bit 5 – PTE – Parity Test Enable

The PTE bit is for test use only. When the PTE bit is set

the parity on the output (SCSI or host processor) bus is

forced to the value of the MSB (bit 7) of the output data

from the internal FIFO. This allows parity errors to be

created to test the hardware and software. The PTE bit

is reset to zero by a hard or soft reset.

CNTLREG1 – Bit 4 – PERE – Parity Error Report-

ing Enable

The PERE bit enables the checking and reporting of par-

ity errors on incoming SCSI bytes during the information

transfer phase. When the PERE bit set and a bad parity

is detected, the PE bit in the STATREG is will be set but

an interrupt will not be generated. In the initiator mode

the

ATN signal will also be asserted on the SCSI bus.

When the PERE bit is reset and a bad parity occurs it is

not detected and no action is taken.

CNTLREG1 – Bit 3 – STE – Self Test Enable

The STE bit is for test use only. When the STE bit is set

the device is placed in a test mode which enables the

device to access the test register at address 0AH. To re-

set this bit and to resume normal operation the device

must be issued a hard or soft reset.

CNTLREG1 – Bit 2:0 – CID 2:0 – Chip ID 2:0

The Chip ID 2:0 bits specify the binary coded value of

the device ID on the SCSI bus. The device will arbitrate

with this ID and will respond to selection or reselection to

this ID. At power-up the state of these bit are undefined.

These bits are not affected by hard or soft reset.

AM53C94JC Datasheet(PDF) 28 Page - Advanced Micro Devices

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