MK20DX256 >> Assembly
LED
參考資訊：
1. ds_pdf
2. pm_pdf
3. example
LED連接到PTC-5
Disable Watchdog
Port Clock
Enable Port
Port Direction
Port Output
main.s
.equiv GPIOC_BASE, 0x400ff080 .equiv GPIO_PDDR, 0x14 .equiv GPIO_PDOR, 0x00 .equiv SIM_BASE, 0x40047000 .equiv SIM_SCGC5, 0x1038 .equiv WDOG_BASE, 0x40052000 .equiv WDOG_STCTRLH, 0x00 .equiv WDOG_UNLOCK, 0x0e .equiv PORTC_BASE, 0x4004b000 .equiv PORTC_PCR5, 0x14 .thumb .cpu cortex-m4 .syntax unified .global _start .text .org 0x0000 _start: .word 0x20008000 .word reset .org 0x0100 .thumb_func reset: ldr r0, =WDOG_BASE ldr r1, =0xc520 strh r1, [r0, #WDOG_UNLOCK] ldr r1, =0xd928 strh r1, [r0, #WDOG_UNLOCK] ldr r1, =0x0000 strh r1, [r0, #WDOG_STCTRLH] ldr r0, =SIM_BASE + SIM_SCGC5 ldr r1, =(1 << 11) str r1, [r0] ldr r0, =PORTC_BASE ldr r1, =(1 << 8) str r1, [r0, #PORTC_PCR5] ldr r0, =GPIOC_BASE ldr r1, =(1 << 5) str r1, [r0, #GPIO_PDDR] 0: eor r1, #(1 << 5) str r1, [r0, #GPIO_PDOR] ldr r2, =1000000 1: subs r2, #1 bne 1b b 0b .end
main.ld
MEMORY {
FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 512K
SRAM (W!RX) : ORIGIN = 0x20000000, LENGTH = 64K
}
SECTIONS {
.text : { *(.text*) } > FLASH
.rodata : { *(.rodata*) } > FLASH
.bss : { *(.bss*) } > FLASH
}
Makefile
all: arm-none-eabi-as -mcpu=cortex-m4 main.s -o main.o arm-none-eabi-ld -T main.ld -o main.elf main.o arm-none-eabi-objcopy -O ihex main.elf main.hex flash: sudo teensy_loader_cli --mcu=mk20dx256 -w main.hex clean: rm -rf main.o main.elf main.hex
編譯、燒錄
1. 連接開發板至PC
2. 按一下燒錄按鍵
3. 執行如下命令
$ make arm-none-eabi-as -mcpu=cortex-m4 main.s -o main.o arm-none-eabi-ld -T main.ld -o main.elf main.o arm-none-eabi-objcopy -O ihex main.elf main.hex $ make flash sudo teensy_loader_cli --mcu=mk20dx256 -w main.hex
完成
