HARDWARE
CPCI-810 User’s Manual
3-3
Revision 1.1, June 2001
3.4
COUNTER/TIMERS
The MPC8240 processor is equipped with four 31-bit on-chip counter/timers which count at 1/8 the
frequency of the SDRAM_CLK signal or 12.5MHz. Users should refer to the Processor User’s Manual
for the functionality and programming of the counters. The timers can be individually programmed to
generate interrupts to the processor when they count down to zero. Two of the timers, timer2 and
timer3, can be set up to automatically start periodic DMA operations for DMA channels 0 and 1,
respectively, without using the processor interrupt mechanism.
3.5
POWER SUPPLY MONITORING
Two circuits are provided for monitoring the health of power supplies. Additional inputs to the
CompactPCI connector define pins for degraded, failed and detected power supplies. The definition for
the CompactPCI connector J2 is provided in Appendix B. A failed or degraded power supply, as long
as it is detected, will cause an interrupt to the processor. Additionally, the state of the power supply as
defined by POWERGOOD, i.e. the power supply is neither degraded or failed, is displayed in a green
LED. Figures 3-1 and 3-2 show the register bit definition for the two power supply status registers.
Figure 3-1. POWER SUPPLY #0 STATUS REGISTER (READ ONLY)
PS0 Failed (1)
PS0 Detected
PS0 Degraded
(Read Only)
7
6
5
4
3
2
1
0
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