Lpc2000

Hi,

I'm trying to start-up the interrupt handling. Herefor I configured Timer0
as IRQ source, and forced an interrupt. But nothing happened.

LPC21xx_VICIntSelect 	= 0x00000000;	// all interrupts are 'IRQ' category
LPC21xx_VICIntEnClr 	= 0xFFFFFFFF;	// clear alle interrupts
LPC21xx_VICIntEnable 	=	IRQ_TIMER_0;	// enable IRQ
LPC21xx_VICDefVectAddr = (UINT32) DefaultInterrupt; // Default IRQ vector
address (for non-vectored irq
LPC21xx_VICVectAddr0 = (UINT32) Timer_OnInterrupt;
LPC21xx_VICVectCntl0 = 0x00000024; // Timer0
 LPC21xx_VICSoftInt = 0x00000010; // bit 4 = Timer0 // force an interrupt -
for test purposes

Then I realized that the IRQ was disabled by next lines in the crt0.s-file:
/* ----------------- */
/* Re-enter SVC mode */
/* ----------------- */
MOV	r0, #Mode_SVC	/* Setup SVC mode */
ORR	r0, r0, #I_Bit	/* IRQ is disabled */
ORR	r0, r0, #F_Bit	/* FIQ is disabled */
MSR     CPSR, r0    	/* Enter SVC mode */
LDR     SP, =SVC_Stack	/* Set stack pointer */

But when I don't set the IRQ-disable-bit, then the code crashes somewhere in
the main-initialisation-code of the GNU compiler.
The PC never gets at @18 (IRQ handler), but at @10 (abourt address)

b	reset_handler	/* @ 0x00 = reset address */
nop			          /* @ 0x04 = undefined address */
b SWI_handler			/* @ 0x08 = SWI address */	
nop			          /* @ 0x0C = prefetch address */	
b ABT_handler			/* @ 0x10 = abort address */	
nop			          /* @ 0x14 = reserved vector */

/*b	IRQ_handler*/	    /* @ 0x18 = IRQ address */		
LDR     PC, [PC, #-0xFF0]	   /* Vector from VicVECAddr */	
b	FIQ_handler	    /* @ 0x1C = FIQ address */		

When the lines:
ORR	r0, r0, #I_Bit	/* IRQ is disabled */
ORR	r0, r0, #F_Bit	/* FIQ is disabled */
are set, the code keeps working normal.

When I try to run the code in USER mode, then it crashes always.

-Compiler is arm-elf-gcc V2.95.2
-I'm using a Nohau debugger for ARM.

My questions are:
-What could be wrong?
-Can someone provide me example source code for GNU-compiler?
-Does the device has to work in user mode, or in service mode?

Thanks.
Pascal Degryze - Belgium