Lpc2000

planiup wrote:
> Hello all:
> 
> I'm a developer of 8 bit microcontrollers applications that wants to 
> switch to ARM. So I'm learning my own all this stuff, and as a 
> newbee, I have some problems. Probably the most stupid ones.
> 
> I have a Macraigor Wiggler clone made by myself, and a development 
> board with an LPC2103, also made by myself. I've checked all 
> circuitry and it seems to be OK.
> 
> I use the IAR KickStart downloaded from IAR, rev 4.30A, and when 
> trying to debug any program with my system, I always start at the 
> bootloader.
> Can somebody point me in the right direction or give me some starting 
> point to avoid that?
> 
> I did not initialize the vector table, since I'm only trying to 
> toggle pin P0.0.
> 

Hi Guillem,

The LPCs expect the vectors area to contain a valid checksum
at the old 24-bit address exception vector location. The
Philips serial port bootloader tool fills in that checksum
when you program a device. The first time I wrote a
simple assembler program to turn on some I/O pins it
didn't work. I filled in the vectors table properly and
then it did. So, I would suggest installing default vectors
that branch to themselves, except for the vector to
start your program of course.

I've attached that example below.

Regards
Dave

# -----------------------------------------------------------------
# Makefile for ex1.elf
# -----------------------------------------------------------------

CC      = arm-elf-gcc
CFLAGS  = -Wall -O2 -mcpu=arm7tdmi

# Override the default linker script .text section start address
LDFLAGS = -Ttext=0 -nostartfiles

# Uncomment this and the linker will output the linker script used
#LDFLAGS += -Wl,--verbose

all: ex1.hex

ex1.elf: ex1.s
	$(CC) $(CFLAGS) $(LDFLAGS) ex1.s -o ex1.elf
	
ex1.hex: ex1.elf
	arm-elf-objcopy -O ihex ex1.elf ex1.hex
	
# Use 'make ex1.size' to see the section sizes 	
ex1.size: ex1.elf
	@echo -n "-------------------------------"
	@echo    "-------------------------------"
	@echo "Object section sizes:"
	@echo -n "-------------------------------"
	@echo    "-------------------------------"
	@echo ""
	arm-elf-size ex1.elf
	@echo ""
	@echo -n "-------------------------------"
	@echo    "-------------------------------"
	@echo ""
	arm-elf-objdump -h ex1.elf
	
clean:
	-rm -rf *.o *.elf *.hex


/* ex1.s */

/* ----------------------------------------------------------------
  * Exception vectors
  * ----------------------------------------------------------------
  */
	.text
	.arm
	.global _start
_start:
	/* Vectors (8 total) */
	b reset   /* reset */
	b loop    /* undefined instruction */
	b loop    /* software interrupt */
	b loop    /* prefetch abort */
	b loop    /* data abort */
	nop       /* reserved for the bootloader checksum */
	b loop    /* IRQ */
	b loop    /* FIQ */

/* ----------------------------------------------------------------
  * Test code
  * ----------------------------------------------------------------
  */
reset:	
	ldr r0, IODIR1
	ldr r1, IODIR1_VALUE
	str r1, [r0]
	ldr r0, IOCLR1
	str r1, [r0]
	ldr r0, IOSET1
	ldr r1, IOSET1_VALUE
	str r1, [r0]

loop:   b   loop

/* ----------------------------------------------------------------
  * Constants
  * ----------------------------------------------------------------
  */
/* LED control registers */
IOSET1:         .word   0xE0028014
IODIR1:         .word   0xE0028018
IOCLR1:         .word   0xE002801C
IODIR1_VALUE:   .word   0x00FF0000
IOSET1_VALUE:   .word   0x00550000

	.end