NUC977 >> Assembly

UART0

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參考資訊：
1. pdf
2. NUC970_NonOS_BSP

GPIO Alternative Function



UART0 TX Buffer


n,8,1


115200bps


main.s

  .equ CLK_PCLKEN0,  (0xb0000200 + 0x18)
  .equ SYS_GPE_MFPL, (0xb0000000 + 0x90)
  .equ UA0_THR,      (0xb8000000 + 0x00)
  .equ UA0_LCR,      (0xb8000000 + 0x0c)
  .equ UA0_BAUD,     (0xb8000000 + 0x24)

  .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, =CLK_PCLKEN0
  ldr r1, [r0]
  orr r1, #(1 << 16)
  str r1, [r0]

  ldr r0, =SYS_GPE_MFPL
  ldr r1, [r0]
  and r1, #0xfffffff0
  orr r1, #0x00000009
  str r1, [r0]

  /* 115200bps */
  ldr r0, =UA0_BAUD
  ldr r1, =0x30000066
  str r1, [r0]
 
loop:
  ldr r0, =UA0_THR
  ldr r1, =0x55
  str r1, [r0]
  ldr r4, =1000000
1:
  subs r4, r4, #1
  bne 1b
  b loop
  .end

完成

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