External Interrupt set by software

eticasas · ‎2004-02-20

Posted on February 20, 2004 at 09:00

eticasas · ‎2011-05-17

Posted on May 17, 2011 at 11:35

Hello All,

About External Interrupts I read on the manual that the IP bit in the EIPR (External Interrupt Pending Bit) may be set by the programmer to implement software interrupt.

My question is this:

Using the instruction: or IDPR,#0x80

may I lose other external edge interrupts that arrive in the while?

(I imagine that the ''or'' instruction implicates a read a set and a writeBack)

thanks for help

kapil · ‎2011-05-17

Posted on May 17, 2011 at 11:35

Yes You can very well trigger external interrupt with the software as you said.

Regarding the second question you are changing the interrupt priority of an Interrupt, so in this case you will not loose interrupt when you are reading the register, doing ORing with the value read, writing back to the register, after this last instruction if you set the priority of interrupt same or lower than the current priority level of MAIN , then you will loose the interrupt.