We have a project with various interrupts. The 1ms C0 timer interrupt is the lowest priority and we would like the RXC uart interrupt to be able to interrupt this timer interrupt.
We have added a asm("sei") instruction at the beginning of the Timer ISR but when we set the timer INTFLAG, the timer routine needs to complete before it then call the Timer ISR again. We are using the JTAG ICE. Is this normal operation?
The problem we have is dropped receive bytes and it appears this is due to an interrupt routine taking too long - ie two serial bytes may be received during timer ISR.
I guess a DMA pipe would fix this but using the DMA does not look straight forward.