Invalid interrupts on mcf5484 serial 0

[phdm]

We have made a board similar to MCF5484Lite one and use uClinux-dist (with added addresses for the mcf5484 serial lines and with slt0 as tick timer) on it.

Whenever we emit simultaneously on serial lines 1 & 2 (PSC1 & PSC2), we get invalid interrupts for PSC0.  This happens after about ten seconds of sending at 4800 bps on PSC1 and at 38400 on PSC2.  PSC0 is not used (TXRDY is masked,

IRQ99 is masked in IMRH and transmitter is disabled in PSC0, and still we receive interrupts on IRQ99, interrupts that we cannot stop, so our system becomes unusable.

Does that seem familiar to someone ?  Is that a known problem of the MCF5484 ?

[phdm · Accepted solution]

Reference manual (13.2.1.6 Interrupt Control Registers 1–63 (ICRn)) says :
"It is software’s responsibility to program the ICRn registers with unique and non-overlapping level and priority definitions. Failure to program the ICRn registers in this matter can result in undefined behavior. "

Well, I had programmed the ICR registers for the four serial lines with the same value (040 (octal)) and those invalid interrupts were the results .