Hi Jeff,
I have tried your port, and it works OK for the led flash demo, but when i tried to make tasks delay it crashed. After a bit of debugging, I discovered your fixed up IRQ stack routine was being executed in the SWI handler, which wwas not being handled by the ROM IRQ handler. Either you need to do both by ROM, or run the non fixed context switch on the SWI routine. I did this and it worked fine. I tried another approach that might be easier to maintain and understand - for the IRQ handler I wrote this simple code in portasm.s79:
vIrqHandler:
PUSH {R0}
LDR R0, vIrqTimerPtr ;get pointer to Timer Status_Control
LDRH R0, [R0, #+0] ;read Status_Control
TST R0, #0x8000 ;see if TCF set
POP {R0} ;finished with temp register
BEQ IrqHandler ;process non RTOS Timer Interrupt
#if configUSE_PREEMPTION == 1
B vPortPreemptiveTickEntry
#else
B vPortNonPreemptiveTick
#endif
vIrqTimerPtr:
DC32 0x8000700e + (0 * 0x20) ;pointer to timer SCTRL register #0
This simple code check our RTOS timer first, if expired process as per standard FreeRTOS ports, otherwise just runs the ROM IRQ handler for the other interrupts. This has the advantage of reduced latency and leaves the bulk of port.C as per LPC2000 demo. It is also independant of ROM versions too. This method would also work well for UCOS-II etc etc.
Regards,
Dean.
