erik malund wrote:
-------------------------------
IE0 is a higher priority interrupt so it can interrupt the RI/TI interrupt.

Read "the bible" ch 3

No interrupt can interrupt an interrupt of the same "IP priority"

Erik

Then the documentation is confusing:

From the "8051 bible" p. 16:

A low-priority interrupt can itself be
interrupted by a high-priority interrupt, but not by another low-priority
interrupt. A high-priority interrupt can’t be interrupted by any other
interrupt source.

Source Priority Within Level
1. IE0 (highest)
2. TF0
3. IE1
4. TF1
5. RI+TI (lowest)

I interpret this to mean that if you are servicing a RI+TI interrupt that you can be interrupted by a IE0 interrupt. Is the above scheme only valid when the IP register is not all zeros? Or does this scheme apply in all cases?


Jacob