ST7FLITE29, PWM out stays HIGH in HALT - mode

[delser9]

Posted on October 23, 2003 at 04:06

ST7FLITE29, PWM out stays HIGH in HALT - mode

[delser9]

Posted on October 14, 2003 at 06:10

In order to save energy in the battery during 'stand-by' we use the HALT mode of the ST7FLITE29.

It seems to work correctly and the current consumption is really very much reduced. But very often, the PWM2 output goes HIGH after the HALT instruction. That must be avoided in the application.

The stand-by routine in C is:

ClearBit(PWMCR,TWO) // Disable PWM1

..

relay_off(); // Turn all outputs OFF

..

ClearBit(PWMCR,FOUR); // Disable PWM2

ClearBit(PADR,FOUR); // Reset PA4 (=PWM2) (not necessary)

WDGCR|=0x7F; // watchdog set

ClearBit(LTCSR1,TB1IE); // active HALT disabled

ClearBit(ATCSR,OVFIE); // ''

ClearBit(PADR,FOUR); // to be sure, that the output is LOW in HALT

(should not be necessary)

Halt; // HALT instruction

Several times, the PWM2 (=PA4) output is set LOW. Does anybody have any idea, why it still stays HIGH in HALT mode? We do have the problem only with the PWM2 and not with PWM1, although they are connected electrically in the same way.

Thank you all for help!

[delser9]

Posted on October 23, 2003 at 04:06

If we add a delay of one second between stopping the PWM and the HALT command it works correctly. The PWM output stays LOW during HALT.

But why? Anybody an idea?

Thank you for any hints!