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INT0 interrupt 18F242 CCS Forum Index -> General CCS C Discussion View previous topic :: View next topic Author Blob

Message INT0 interrupt 18F242 Posted: Mon Jan 02, 2006 6:56 am

Joined: 02 Jan 2006 Posts: 3 Location: Geistingen, Limburg, Belgium

Hello, At the moment i'm trying to generate an external interrupt on the PIC 18F24. i want to generate the interrupt on pin RB0. but it seems the interrupt is not catched... the code i use is as below: #include <18F242.H> #fuses HS,NOWDT, NOPROTECT, PUT #use DELAY (clock=20000000) #use fast_io(A) #use fast_io(B) //int i; //int x; //int c; #int_ext void EXT_ISR() { output_high(PIN_A0); delay_ms(200); delay_ms(200); delay_ms(200); delay_ms(200); delay_ms(200); delay_ms(200); output_high(PIN_A0); } /* main() */ void main() {

1 от 3

01.3.2007 г. 11:24

CCS :: View topic - INT0 interrupt 18F242

http://ccsinfo.com/forum/viewtopic.php?t=25558&highlight=inte...

/* Set pin A1 to be the blue led */ SET_TRIS_A(0x00); /* Allow pin B0 to be an external interrupt pin */ SET_TRIS_B(0b00010000); ext_int_edge(H_TO_L); enable_interrupts(global); enable_interrupts(int_rb); while(1) { output_high(PIN_A3); } }

Greets, Blob _________________ IMEC rulez ckielstra

Joined: 18 Mar 2004 Posts: 1334 Location: The Netherlands

Posted: Mon Jan 02, 2006 8:39 am

Code: /* Allow pin B0 to be an external interrupt pin */ SET_TRIS_B(0b00010000);

You are configuring B4 as an input but your comment says B0. Code: #int_ext void EXT_ISR() { output_high(PIN_A0); delay_ms(200); delay_ms(200); delay_ms(200); delay_ms(200); delay_ms(200); delay_ms(200); output_high(PIN_A0); }

Change one of the output_high() calls to output_low(). And why do you call 6 x delay_ms(200) when one call to delay_ms(1200) would do the same? Humberto

Joined: 08 Sep 2003 Posts: 813 Location: Buenos Aires la Reina del Plata

Posted: Mon Jan 02, 2006 11:26 am

Quote: At the moment i'm trying to generate an external interrupt on the PIC 18F242. i want to generate the interrupt on pin RB0. but it seems the interrupt is not catched...

enable_interrupts(int_rb); Should be enable_interrupts(INT_EXT); I assume you have a pull-up resistor wired from +5V to PIN RB0 or: port_b_pullups(TRUE); declared in your code. It is not a good practice to use delays inside an interrupt handler !!! To 'see' the RB0 interrupt action, the following code should be enough. (If your compiler version has the output_toggle() function.)

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01.3.2007 г. 11:24

CCS :: View topic - INT0 interrupt 18F242

http://ccsinfo.com/forum/viewtopic.php?t=25558&highlight=inte...

Code: #int_ext void EXT_ISR() { output_toggle(PIN_A0); }

or if it doesn't: Code: int8 ext_trigger; #int_ext void EXT_ISR() { output_high(PIN_A0); ext_trigger = TRUE; } void main() { while(1) { ....... your stuff ....... if(ext_trigger) { delay_ms(200); output_low(PIN_A0); delay_ms(200); ext_trigger = FALSE; } } }

Best wishes, Humberto Display posts from previous: All Posts

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01.3.2007 г. 11:24