interrupt handling

[Ryan]

I usde two interrupts in my program but while one interrupt was being handeled another interrupt got generated ,it was also of  higher priority but the interrupt did not got executed. what could be the possible problem?

is the controller(at89c51)not able to handle two interrupts at a time. if yes is it valid for all controllers of other series too

[SHAH DISHANT H.]

Hi,

Can you post the code here? If you want, you can use masking of interrupt. 

[Ashutosh Bhatt]

in 8051 based system, second interrupt service routine will not be executed till the on going ISR is completed. the priority only works when two interrupts occurs at the same time. 

[SHAH DISHANT H.]

Hello Mr. A M Bhatt

 

As far as I know, Higher prority interrupt can tregger lower priority interrupt. I have made one application which is as followed.

 

When the system will receive data RI will occur and in interrupt 4 I had written a ISR which will receive data on UART unless it receives ‘*’ on UART.

 

I had connected a fire sensor on EXT0 and when this interrupt will occur, it will start running one motor. 

 

Here if UART is receiving data and it still hs not received ‘*’ and if EXT0 will receive interrupt, it will stop running ISR of interrupt4 and will go to ISR 1. After  completting ISR1, it will return to ISR4 and will wait till ‘*’ has been received.

 

Check with such conditions.

 

I may be wrong but this is what I had tried and it was working fine.

[Author]

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