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Using Hardware Interrupt (INT0) CCS Forum Index -> General CCS C Discussion View previous topic :: View next topic Author ericzuki

Message Using Hardware Interrupt (INT0) Posted: Mon Mar 08, 2004 9:41 am

Joined: 24 Feb 2004 Posts: 3

Hi All I have written a test program on INT0 but I am not able to test it out on the hardware yet due to unavalibility. Can someone be kind enough to tell me whether the code will works. A push button is connected to Pin B0 which when pushed will caused the chip to go into SLEEP mode. A second push on the pushbutton will bring the chip active and reset via reset_cpu().

Code: #include <18F458.h> #fuses HS,NOWDT,NOPROTECT,NOLVP #use delay(clock=20000000) // global flag to send processor into sleep mode short sleep_mode; // external interrupt when button pushed and released #INT_EXT void ext_isr() { if(button_pressed_once) // if button action and was not // pressed { button_pressed_once=FALSE; //to activate the next button pressed // which is to reset the thing sleep(); } else { button_pressed_once=TRUE; // the button is now up reset_cpu(); } } void main() { ext_int_edge(H_TO_L); // init interrupt triggering for button press enable_interrupts(INT_EXT);// turn on interrupts enable_interrupts(GLOBAL); static short button_pressed_once=TRUE; }

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27.2.2007 г. 09:48

CCS :: View topic - Using Hardware Interrupt (INT0)

http://ccsinfo.com/forum/viewtopic.php?t=18610&highlight=int0...

Thanks jds-pic

Re: Using Hardware Interrupt (INT0) Posted: Mon Mar 08, 2004 9:09 pm

Joined: 17 Sep 2003 Posts: 168

ericzuki wrote:

Code: #INT_EXT void ext_isr() { if(button_pressed_once)

// if button action and was not // pressed

{ button_pressed_once=FALSE; //to activate the next button pressed // which is to reset the thing sleep(); } else { button_pressed_once=TRUE; // the button is now up reset_cpu(); } } void main() { ext_int_edge(H_TO_L); // init interrupt triggering for button press enable_interrupts(INT_EXT);// turn on interrupts enable_interrupts(GLOBAL); static short button_pressed_once=TRUE; }

it may just be me but i don't like the idea of going to sleep inside an interrupt handler function. i believe that this is asking for debugging troubles and it's just not good programming practice. why not just set a flag in #int_ext and test it in main()? keep your inerrupt handlers simple. jds-pic Display posts from previous: All Posts

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27.2.2007 г. 09:48