Problem clearing pending interrupt in MISR

[jens239955_st]

Posted on June 09, 2006 at 10:58

Problem clearing pending interrupt in MISR

[jens239955_st]

Posted on May 23, 2006 at 04:49

Hello Everyone,

I'm working on a motor control solution with the ST7 in combination with a igbt power module. I got a problem while trying to implement a simple detection of the module failure feedback signal, connected to the /MCES pin of the ST7. I simply enabled the emergency stop interrupt in the MIMR register and implemented the interrupt service routine for the emergency stop and speed error interrupts.

Everything works fine (when I pull the /MCES pin low the interrupt service routine is called), except clearing the pending interrupt flag of the emergency stop by

MISR = ((unsigned char)~MISR_EI_OR);

If I leave the /MCES pin low and clear the interrupt flag, the interrupt service routine is called again and again, even when writing MISR = 0;

According to the ST7 user manual, the emergency stop interrupt flag will only be set when detecting an edge on the /MCES pin, not when the pin is in a static low state.

I don't know what to try anymore. Can anyone help me?

Thanks in advance!

[pjr]

Posted on June 09, 2006 at 10:58

The way I read the datasheet for the ST7MC1 on page 138 the emergency stop pin is ''active low'' which makes it level sensitive and not edge sensitive.

pjr