48 lines
676 B
ArmAsm
48 lines
676 B
ArmAsm
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.global sk6812_send_led
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.equ BSRR_REGISTER, 0x48000018
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.equ PINNUM, 3
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.syntax unified
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sk6812_send_led:
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push {lr}
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push {r4, r5, r6}
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ldr r1, =BSRR_REGISTER
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ldr r2, =(1<<PINNUM)
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ldr r3, =(1<<(PINNUM+16))
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ldr r4, =32
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ldr r5, =0x80000000
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_bitloop:
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tst r0, r5
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beq sk6812_send_zero
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bne sk6812_send_one
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_bitloop_ret:
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lsls r0, r0, #1
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subs r4, r4, #1
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bne _bitloop
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pop {r4, r5, r6}
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pop {pc}
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sk6812_send_one:
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str r2, [r1]
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ldr r6, =0x5
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bl wait_r6
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str r3, [r1]
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ldr r6, =0x2
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bl wait_r6
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b _bitloop_ret
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sk6812_send_zero:
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str r2, [r1]
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ldr r6, =0x1
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bl wait_r6
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str r3, [r1]
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ldr r6, =0x5
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bl wait_r6
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b _bitloop_ret
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wait_r6:
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subs r6, r6, #1
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bne wait_r6
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bx lr
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