Search code examples
serial-portmicrocontrollerpicwakeup

Wake PIC16F1825 from sleep with RS232

Is it possible to wake a Microchip PIC16F1825 from sleep using RS232 without looking characters?

Because one of the permissible RX pins supports interrupt on change, I thought this might be possible.

Has anybody implemented this successfully?

Solution

  • Sure!

    From datasheet PIC16(L)F1825/1829:

    9.1 Wake-up from Sleep

    The device can wake-up from Sleep through one of the following events:
1. External Reset input on MCLR pin, if enabled
2. BOR Reset, if enabled
3. POR Reset
4. Watchdog Timer, if enabled
5. Any external interrupt
6. Interrupts by peripherals capable of running 
   during Sleep (see individual peripheral for more information)

    So you can use:

    1)External interrupt INTERRUPT-ON-CHANGE, if you are connecting RX pin with one of other pins which is configured as interrupt-on-change.

    2)Peripheral interrupt RCIF: USART Receive Interrupt Flag bit. When receiver buffer is full (one UART word is received), an interrupt is pending and your CPU should wake up.