155 lines
3.5 KiB
ArmAsm
155 lines
3.5 KiB
ArmAsm
.export _SD_command
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.export _SD_readRes1
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.export _SD_readRes2
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.export _SD_readRes3
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.export _SD_readBytes
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.export _res1_cmd
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.importzp sp, ptr1
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.autoimport on
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.MACPACK generic
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; void SD_command(uint8_t cmd, uint32_t arg, uint8_t crc)
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; The plan: push crc to stack, load arg into tmp1 through 4
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.proc _SD_command: near
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pha ; Push CRC to cpu stack
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ldy #$04
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lda (sp),y ; Load CMD
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ora #$40 ; start bit
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jsr _spi_exchange
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dey
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arg_loop: ; send ARG
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lda (sp),y
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jsr _spi_exchange
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dey
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bpl arg_loop
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pla ; Pull CRC from stack
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ora #$01 ; stop bit
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jsr _spi_exchange
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jsr incsp5 ; pop all off stack
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rts
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.endproc
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; uint8_t SD_readRes1 (void)
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.proc _SD_readRes1: near
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; Try to read/write up to 8 times, then return value
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ldx #$08
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tryread:
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lda #$ff
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jsr _spi_exchange
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cmp #$ff
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bne end
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dex
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bne tryread
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end: ; x will be 0 here anyway
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rts
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.endproc
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; void SD_readRes2(uint8_t *res)
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.proc _SD_readRes2: near
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sta ptr1 ; store res in ptr1
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stx ptr1 + 1
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jsr _SD_readRes1 ; get first response 1
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sta (ptr1)
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lda #$ff
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jsr _spi_exchange ; get final byte of response
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ldy #$01
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sta (ptr1),y
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jsr incsp2
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rts
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.endproc
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; void SD_readBytes(uint8_t *res, uint8_t n)
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.proc _SD_readBytes: near
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tax
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jsr popptr1 ; store res in ptr1
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read:
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lda #$ff ; read data first
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jsr _spi_exchange
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sta (ptr1)
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inc ptr1 ; then increment res
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bne @L1
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inc ptr1 + 1
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@L1: dex ; then decrement x
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bne read ; and if x is zero we are done
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rts
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.endproc
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; void SD_readRes3(uint8_t *res)
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.proc _SD_readRes3: near
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sta ptr1 ; store res in ptr1
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stx ptr1 + 1
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jsr _SD_readRes1 ; read respopnse 1 in R3
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cmp #$02 ; if error reading R1, return
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bge @L1
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inc ptr1 ; read remaining bytes
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bne @L2
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inc ptr1
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@L2: lda ptr1 ; push low byte
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sta (sp)
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ldy #$01
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lda ptr1 + 1 ; push high byte
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sta (sp),y
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lda #$04 ; R3_BYTES
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jsr _SD_readBytes
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@L1: rts
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.endproc
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; uint8_t res1_cmd(uint8_t cmd, uint32_t arg, uint8_t crc)
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.proc _res1_cmd: near
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pha ; push crc to processor stack
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lda #$ff
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jsr _spi_exchange
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lda #$00 ; this gets ignored anyway
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jsr _spi_select
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lda #$ff
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jsr _spi_exchange
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pla
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jsr _SD_command ; rely on command to teardown stack
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jsr _SD_readRes1
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tay ; spi doesn't touch y
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lda #$ff
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jsr _spi_exchange
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lda #$00 ; this gets ignored anyway
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jsr _spi_deselect
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lda #$ff
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jsr _spi_exchange
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tya
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ldx #$00 ; Promote to integer
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rts
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.endproc |