Posted on April 05, 2005 at 17:33Inherited an Elite based design running QNX. 2 issues observed: a PCI 10/100 NIC drives INTA to IRQ 11 through STPC internal programmed connection. Correct IRQ routine runs roughly 90-95% of the time. When it doesn't, NIC get stuck with IRQ asserted and all IRQ priorities 3 and up get bogged (IRQ2 is the slave bridge level). Machine seems to respond to all IRQs, however, it appears as if the PIC issues the wrong vector intermittently, but only for the IRQ coupled over from PCI INTA as all other IRQs work fine. Anyone see this before?
Issue 2 is equally strange. In one instance of system hang due to issue 1, PCI CLK was found to be running at over 120MHz, versus its normal 33MHz. CPU Reset of any duration would not recover it, and a full power-off/on cycle was needed to restore normal clock. I didn't check it at the time, but I speculate that the strap ports MD6-7 were driven high either by the SDRAMs or the controller, presenting an invalid PCI PLL selection. using 50K pulldowns (Trc approx 5usec), it should have cleared with millisecond long reset pulses. I saw the postings regarding 1K pulldowns, but I don't think this is the case as I manually held the reset for seconds and it still didn't clear. :-?
