EINT0

Development Boards MicroMod
1

I’m trying to get EINT0 running. I can setup the VIC but cannot figure out how to associate the VIC channel with EINT0. The FIQ_Handler is mapped in my interrupt vector table.

boot code linking ISR:

Vectors         LDR     PC, Reset_Addr         
                LDR     PC, Undef_Addr
                LDR     PC, SWI_Addr
                LDR     PC, PAbt_Addr
                LDR     PC, DAbt_Addr
                NOP                            ; Reserved Vector 
;               LDR     PC, IRQ_Addr
                LDR     PC, [PC, #-0x0120]     ; Vector from VicVectAddr
                LDR     PC, FIQ_Addr

				IMPORT FIQ_Handler

Reset_Addr      DCD     Reset_Handler
Undef_Addr      DCD     Undef_Handler
SWI_Addr        DCD     SWI_Handler
PAbt_Addr       DCD     PAbt_Handler
DAbt_Addr       DCD     DAbt_Handler
                DCD     0                      ; Reserved Address 
IRQ_Addr        DCD     IRQ_Handler
FIQ_Addr        DCD     FIQ_Handler

Undef_Handler   B       Undef_Handler
SWI_Handler     B       SWI_Handler
PAbt_Handler    B       PAbt_Handler
DAbt_Handler    B       DAbt_Handler
IRQ_Handler     B       IRQ_Handler

Main code:

#include "lpc246x.h"

void FIQ_Handler( void )  __irq
{
	// Pulling Port1.18 high turns off the LED
	IOSET1 = 0x00040000;	
	
	// I don't reset the interrupt flag as I just
	// want to see that I can vector here at this point.
}

int main( void )
{
	/* Setup green LED by EINT0 button.  This is next to the
	"Good" silk screen message.  By default the LED is off on power
	up.  Once Port1.18 is configured as an output the LED
	illuminates.

	Pulling Port1.18 high turns off the LED.
	Pulling Port1.18 low turns off LED.
	*/
	
	PINSEL3 &= 0xFFFFFFCF;		// Set Port1.18 to GPIO
	IODIR1   = 0x00040000;		// Set Port1.18 to Output

	// LED is on now.  It should turn off once EINT0 is tripped.



	/* Configure External Interrupt 0 / Port2.10
	Note: Port2.10 serves only one function EINT0 so by default
	it is always hooked up to that port. */
	
	// Set Interrupt channel 0 as FIQ
	VICIntSelect = 0x00000001;

	// Set address for channel 0 ISR
	VICVectAddr0 = (unsigned)FIQ_Handler;

	// Turn on Interrupt channel 0
	VICIntEnable = 0x00000001;		// Enable interrupt channel 0
	
	/* I'm confused at this point.  I cannot find anyplace that tell
	me the EINT0 is on.  And I would expect a 5-bit setting
	somplace to tell EINT0 which interrupt channel in the VIC contains
	the ISR. I think if I had that I'd be up and running right now. */
	
	while( 1 );	// Loop here forever

	return 0;
}
2

I am having the exact same problem on the same board. Did you find a solution or does anyone have any suggestions?

Thanks.

3

here’s what I use for interrupts from a WizNet 812MJ to an LPC2106, active-low, plus a pull-up resistor…

    VICIntSelect &= ~(1<VIC_EINT0);              // GPIO ext0 interrupt not Fast IRQ
    VICVectAddr4 = (unsigned int) &Wiz5100ISR;  // Install ISR in VIC addr slot n
    VICVectCntl4 = 0x20 | VIC_EINT0;            // IRQ enable, and its number 
    VICIntEnable |= (1<<VIC_EINT0);             // Turn on  Interrupt

(IAR code)

Beware: some LPCs prior to rev /01 do not implement edge-triggered EINTn; Only level sensitive. So the ISR must tell the device to drop it’s interrupt request.