LPC2103: Issue with instruction at reset

Development Boards MicroMod
1

I’m using an LPC2103 and openocd to build a robotics project. I’m having one small problem though. The first instruction out of reset is not being executing and when I use openocd to disassemble it reads nothing at address 0x0. As can be seen below the instruction at reset should be effectively a branch to my reset function. From there I set-up the stack, data, and bss sections, and I make a jump to main code.

_start:
	ldr   pc,_reset             
        ldr   pc,_undf                  
        ldr   pc,_swi                   
        ldr   pc,_pabt                  
        ldr   pc,_dabt                  
        nop                             
        ldr   pc,[pc,#-0xFF0]           
        ldr   pc,_fiq                   
	
	_reset: .word __reset
	_undf:  .word __undf                    
	_swi:   .word __swi                     
	_pabt:  .word __pabt                    
	_dabt:  .word __dabt                    
	_irq:   .word __irq                     
	_fiq:   .word __fiq                     
	
	__reset: b _init
	__undf: b     .	        	        
	__swi:  b     .                         
	__pabt: b     .		                
	__dabt: b     .		                
	__irq:  b     .                         
	__fiq:  b     .

Instead based on the output of the assemble below there is nothing at 0x00.

> armv4_5 disassemble 0x0 10
0x00000000      0x00000000      ANDEQ r0, r0, r0
0x00000004      0xe59ff018      LDR r15, [r15, #0x18]
0x00000008      0xe59ff018      LDR r15, [r15, #0x18]
0x0000000c      0xe59ff018      LDR r15, [r15, #0x18]
0x00000010      0xe59ff018      LDR r15, [r15, #0x18]
0x00000014      0x9ec04f9c      MCRLS p15, 0x06, r4, c0, c12, 0x04
0x00000018      0xe51ffff0      LDR r15, [r15, #-0xff0]
0x0000001c      0xe59ff014      LDR r15, [r15, #0x14]

So far I’ve checked that my linker, my openocd config file, and the command I use to load code into flash in openocd and all are set to load code at an offset of 0x0 at address 0x0. Below is the cmd in openocd I use to load code to flash.

 flash write_binary 0x0 /home/phillip/RoboJackets/RoboCup/firmware/robot/robot0.bin 0x0
wrote  3840 byte from file /home/phillip/RoboJackets/RoboCup/firmware/robot/robot0.bin to flash bank 0 at offset 0x00000000 in 1s 219959us (3.073874 kb/s)
2

Hi

Are you sure that the chip is not startig up in ISP mode due to the check sum at the unused vector location not being correct?

[This probably doesn’t explain why you see 0x00000000 at the reset vector location though].

Regards

Mark

http://www.uTasker.com