NEC Network Controller uPD98502 - Manual (Page 133)

CHAPTER 2 V R 4120A
Preliminary User’s Manual S15543EJ1V0UM 133
2.5.3.4 Compare register (11)
The Compare register causes a timer interrupt; it maintains a stable value that does not change on its own.
When the value of the Count register (see Section 2.5.3.3 Count register (9)) equals the value of the Compare
register, the IP7 bit in the Cause register is set. This causes an interrupt as soon as the interrupt is enabled.
Writing a value to the Compare register, as a side effect, clears the timer interrupt request.
For diagnostic purposes, the Compare register is a read/write register. Normally, this register should be only used
for a write. Figure 2-50 shows the format of the Compare register.
Figure 2-50. Compare Register Format
32
0 31
Compare
Compare: Value that is compared with the count value of the Count register.