LPC2103 >> Assembly
UART
參考資料：
1. pdf
暫存器
main.s
.equ IODIR, 0xe0028008
.equ IOCLR, 0xe002800c
.equ IOSET, 0xe0028004
.equ PINSEL0, 0xe002c000
.equ U0LCR, 0xe000c00c
.equ U0DLL, 0xe000c000
.equ U0DLM, 0xe000c004
.equ U0THR, 0xe000c000
.text
.align 2
.global _start
_start: b reset
_undef: b .
_swi: b .
_pabort: b .
_dabort: b .
_reserved: b .
_irq: b .
_fiq: b .
reset:
ldr r0, =PINSEL0
ldr r1, =0x05
str r1, [r0]
ldr r0, =U0LCR
ldr r1, =0x83
str r1, [r0]
/* 9600bps */
/* 12000000 / 16 / 4 / 9600 = 0x13 */
ldr r0, =U0DLM
ldr r1, =0x00
str r1, [r0]
ldr r0, =U0DLL
ldr r1, =0x13
str r1, [r0]
ldr r0, =U0LCR
ldr r1, =0x03
str r1, [r0]
loop:
ldr r4, =50000
1:
nop
subs r4, r4, #1
bne 1b
ldr r0, =U0THR
ldr r1, =0x55
str r1, [r0]
b loop
.end
完成
