AM53C96 datasheet(37/63 Pages) AMD

37 / 63 page

P R E L I M I N A R Y

AMD

Am53C94/Am53C96

Status Register (STATREG) 04H will be set. This com-

mand is cleared from the command queue once it is

decoded.

Caution must be exercised when using this command.

The DMA Stop Command can be used only during a

DMA Target Send Data Command or DMA Target Re-

ceive Data Command execution. In both cases the DMA

controller has to be in the idle state.

During a DMA Target Send Data Command the FIFO

has to be empty or the Current FIFO (CF 4:0) bits in the

Current FIFO/Internal State Register (CFISREG) 07H

are zero.

During a DMA Synchronous Target Receive Data Com-

mand the Current Transfer Count Register (CTCREG)

00–01H is zero, which is indicated by the Count to Zero

(CTZ) bit of the Status Register (STATREG) 04H. or

when the Synchronous Offset Register (SOFREG) 07H

has reached its maximum value which is indicated by

the Synchronous Offset Flag (SOF) bit of the Internal

State Register (ISREG) 06H.

During a DMA Asynchronous Target Receive Data

Command the FIFO is full which is indicated by the Cur-

rent FIFO (CF 4:0) bits in the Current FIFO/Internal

State Register (CFISREG) 07H being all high or Current

Transfer Count Register (CTCREG) 00–01H is zero,

which is indicated by the Count to Zero (CTZ) bit of the

Status Register (STATREG) 04H.

Idle State Commands

The Idle State Commands can be issued to the device

only when the device is disconnected from the SCSI

bus. If these commands are issued to the device when it

is logically connected to the SCSI bus, the commands

are ignored, and the device will generate an illegal com-

mand interrupt and clear the Command Register

(CMDREG) 03H.

Reselect Steps Command

(Command Code 40H/C0H)

The Reselect Steps Command is used by the target de-

vice to reselect an initiator device. When this command

is issued the device arbitrates for the control of the SCSI

bus. If the device wins arbitration, it reselects the initia-

tor device and transfers a single byte identify message.

Before issuing this command the SCSI Timeout Regis-

ter (STIMREG) 05H, the Control Register One

(CNTLREG1) 08H and the SCSI Destination ID Regis-

ter (SDIDREG) 04H must be set to the proper values. If

DMA is enabled, the Start Transfer Count Register

(STCREG) 00H–01H must be set to one. If DMA is not

enabled, the single byte identify message must be

loaded into the FIFO before issuing this command. This

command will be terminated early if the SCSI Timeout

nal State Register (ISREG) 06H.

Select without ATN Steps Command

(Command Code 41H/C1H)

The Select without ATN Steps Command is used by the

initiator to select a target. When this command is issued

the device arbitrates for the control of the SCSI bus.

When the device wins arbitration, it selects the target

device and transfers the Command Descriptor Block

(CDB). Before issuing this command the SCSI Timeout

(CNTLREG1) 08H and the SCSI Destination ID Regis-

ter (SDIDREG) 04H must be set to the proper values. If

DMA is enabled, the Start Transfer Count Register

(STCREG) 00H–01H must be set to the total length of

the command. If DMA is not enabled, the data must be

loaded into the FIFO before issuing this command. This

command will be terminated early if the SCSI Timeout

Command Phase following the Selection Phase or if the

target exits the Command Phase early.

Select with ATN Steps Command

(Command Code 42H/C2H)

The Select with ATN Steps Command is used by the in-

itiator to select a target. When this command is issued

the device arbitrates for the control of the SCSI bus.

When the device wins arbitration, it selects the target

device with the

ATN signal asserted and transfers the

Command Descriptor Block (CDB) and a one byte mes-

sage. Before issuing this command the SCSI Timeout

(CNTLREG1) 08H and the SCSI Destination ID Regis-

ter (SDIDREG) 04H must be set to the proper values. If

DMA is enabled, the Start Transfer Count Register

(STCREG) 00H–01H must be set to the total length of

the command. If DMA is not enabled, the data must be

loaded into the FIFO before issuing this command. This

command will be terminated early in the following situ-

ations:

s The SCSI Timeout Register times out

s The target does not go to the Message Out Phase

following the Selection Phase

s The target exits the Message Phase early

s The target does not go to the Command Phase

following the Selection Phase

s The target exits the Command Phase early.

Select with ANT and Stop Steps Command

(Command Code 43H/C3H)

The Select with ATN and Stop Steps Command is used

by the initiator to select a target. When this command is

issued the device arbitrates for the control of the SCSI

bus. When the device wins arbitration, it selects the tar-

get device with the

ATN signal asserted and transfers

the Command Descriptor Block (CDB) and stops after

one message byte is sent, but the

ATN signal is not

AM53C96 Datasheet(PDF) 37 Page - Advanced Micro Devices

AM53C96 Datasheet(HTML) 37 Page - Advanced Micro Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63

Datasheet Download

Link URL