Lpc2000

Hi Pascal,

If you need a simple & effective startup code check my
ARM UCOS port it has a startup code along with linker
script.

http://geocities.com/michaelanburaj/downlaod/arm_ucos_1.3.zip

cheers,
-Mike.

--- Pascal Degryze <pascal.degryze@...>
wrote:
> 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
> 


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