HTH [3:0]

Minimum Time-out

Minimum Time-out

SEL [3:0]

(80 MHz Clock) With

(80 MHz Clock) With

GEN [3:0]

Scale Factor Bit Cleared1

Scale Factor Bit Set

 

 

 

0000

Disabled

Disabled

 

 

 

0001

100 s

1.6 ms

 

 

 

0010

200 s

3.2 ms

 

 

 

0011

400 s

6.4 ms

 

 

 

0100

800 s

12.8 ms

 

 

 

0101

1.6 ms

25.6 ms

 

 

 

0110

3.2 ms

51.2 ms

 

 

 

0111

6.4 ms

102.4 ms

 

 

 

1000

12.8 ms

204.8 ms

 

 

 

1001

25.6 ms

409.6 ms

 

 

 

1010

51.2 ms

819.2 ms

 

 

 

1011

102.4 ms

1.6 s

 

 

 

1100

204.8 ms

3.2 s

 

 

 

1101

409.6 ms

6.4 s

 

 

 

1110

819.2 ms

12.8 s

 

 

 

1111

1.6 + s

25.6 s

 

 

 

1.These values are correct if the CCF bits in the SCSI Control Three (SCNTL3) register are set according to the valid combinations in the bit description.

SEL[3:0] Selection Time-Out[3:0]

These bits select the SCSI selection/reselection time-out period. When this timing (plus the 200 s selection abort time) is exceeded, the STO bit in the SCSI Interrupt Status One (SIST1) register is set. For a more detailed explanation of interrupts, refer to Chapter 2, “Functional Description.”

4-84Registers

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Image 176
LSI 53C875A technical manual SEL30 Selection Time-Out30