ST10F273 fast external interrupt pproblem

[ggraf]

Posted on January 14, 2009 at 09:45

ST10F273 fast external interrupt pproblem

[ggraf]

Posted on January 14, 2009 at 09:45

Hi,

I am using the ST10F273 and I have an external peripheral (A2D) which needs to be serviced by the ST10F273. It signals it's readiness to be serviced via a falling edge signal on adigital IO connected to the ST10F273 P2.13 pin. I have configured P2.13 as an input and set up everything to cause the interrupt to happen. The problem is I get variable and very long latency (up to 80us) between the falling edge on P2.13 and the invocation of the ISR?? Here is the code I use to configure the fast external interrupt:

>>>>>>

// Fast external interrupt on falling edge

EXICON = 0x800;

// Capture on falling edge

CCM3 = 0x20;

// Set interrupt level and group

CC13IC = ADC_READ_GLVL | (ADC_READ_ILVL << 2) ;

// Enable interrupt

CC13IE = 1;

>>>>>>

Am I doing something wrong??

Thanks

Glenn