EV-LM3S811 blinking LED in assembler
For the really hard core folk that want to get to the bare metal of the new Stellaris parts, here is a minimal program that will blink the user LED on the EV-LM3S811 board, in glorious ARM assembler code, which will compile under the uVision demo that is supplied with the evaluation kit:
; blink.s - blink user LED on Luminary Micro EV-LM3S811 (Cortex-M3)
AREA TEXT, CODE, READONLY
CODE16
; vector table
DCD 0x20002000
DCD Reset_Handler
DCD iloop
DCD iloop
; start the program here
Reset_Handler
EXPORT Reset_Handler
; initialize GPIO port C, pin 5 as output
RCGC2 EQU 0x400FE108 ; run-mode clock gating control 2
RCGC2_PORTC EQU 1 << 2 ; PORTC clock enable
ldr r0, =RCGC2
ldr r1, =RCGC2_PORTC
str r1, [r0]
GPIODIR_PORTC EQU 0x40006400
GPIO_PC5 EQU 1 << 5
ldr r0, =GPIODIR_PORTC
ldr r1, =GPIO_PC5
str r1, [r0]
GPIODATA_PORTC EQU 0x40006000
ldr r0, =GPIODATA_PORTC + (GPIO_PC5 << 2)
loop
ldr r1, =GPIO_PC5
str r1, [r0]
ldr r2, =1000000
1 subs r2, r2, #1
bne %1
ldr r1, =0
str r1, [r0]
ldr r2, =1000000
1 subs r2, r2, #1
bne %1
b loop ; and do it again
; an infinite loop in place of real exception handlers
iloop b iloop
; the end
END
[end-of-file]
Note that you will need to indent all the lines that don't start with a label, as this forum is protecting you from my code in its original beauty.
Questions? Comments? Let me know!
Dale
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