LSI 53C810A - Manual (Page 132)

5-58 Operating Registers
SEL Selection Time-Out [3:0]
These bits select the SCSI selection/reselection time-out
period. When this timing (plus the 200
µ
s selection abort
time) is exceeded, the STO bit in the SCSI Interrupt Sta-
tus One (SIST1) register is set. For a more detailed
explanation of interrupts, refer to Chapter 2, “Functional
Description.”
Register: 0x49 (0xC9)
SCSI Timer One (STIME1)
Read/Write
R Reserved [7:4]
GEN[3:0] General Purpose Timer Period [3:0]
These bits select the period of the general purpose timer.
The time measured is the time between enabling and
disabling of the timer. When this timing is exceeded, the
0110 4 ms 3.2 ms
0111 8 ms 6.4 ms
1000 16 ms 12.8 ms
1001 32 ms 25.6 ms
1010 64 ms 51.2 ms
1011 128 ms 102.4 ms
1100 256 ms 204.8 ms
1101 512 ms 409.6 ms
1110 1.024 s 819.2 ms
1111 2.048 s 1.6384 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.
HTH[7:4],
SEL[3:0],
GEN[3:0]
1
Minimum Timeout
(40 MHz)
Minimum Timeout
(50 MHz)
7 4 3 0
R GEN[3:0]
x x x x 0 0 0 0