Register: 0x52

SCSI Test Four (STEST4)

Read Only

7

 

6

5

4

 

 

 

0

R

 

 

LOCK

 

 

R

 

 

x

 

x

 

0

x

x

x

x

x

R

 

Reserved

 

 

 

 

[7:6]

LOCK

 

Frequency Lock

 

 

 

5

 

 

 

This bit is used when enabling the SCSI clock quadrupler,

 

 

 

which allows the LSI53C875A to transfer data at Ultra

 

 

 

SCSI rates. Poll this bit for a 1 to determine that the clock

 

 

 

quadrupler has locked. For more information on enabling

 

 

 

the clock quadrupler, refer to the descriptions of SCSI

 

 

 

Test One (STEST1), bits 2 and 3.

 

 

R

 

Reserved

 

 

 

 

[4:0]

Register:

0x53

 

 

 

 

 

Reserved

 

 

 

 

 

 

 

 

Registers: 0x54–0x55

SCSI Output Data Latch (SODL)

Read/Write

15

0

SODL

x x

x x

x

x

x

x

x

x

x

x

x

x

x

x

SODL SCSI Output Data Latch[15:0]

This register is used primarily for diagnostic testing or programmed I/O operation. Data written to this register is asserted onto the SCSI data bus by setting the Assert Data Bus bit in the SCSI Control One (SCNTL1) register. This register is used to send data using programmed I/O. Data flows through this register when sending data in any mode. It is also used to write to the synchronous data FIFO when testing the chip. The power-up value of this register is indeterminate.

4-94Registers

Page 186
Image 186
LSI 53C875A technical manual Register 0x53, Lock