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tashtwenty
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20211106

This commit is contained in:
lampmerchant 2021-11-06 11:36:59 -06:00
parent 5a4ccc88a4
commit 491df43e51
1 changed files with 96 additions and 34 deletions
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130
firmware/tashtwenty.asm
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@ -80,6 +80,9 @@ TXNOTRC equ 7 ;Set if a transmit is ongoing, clear if a receive is
M_FAIL equ 7 ;Set when there's been a failure on the MMC interface
M_CMDLR equ 6 ;Set when R3 or R7 is expected (5 bytes), not R1
M_CMDRB equ 5 ;Set when an R1b is expected (busy signal after reply)
M_MBRD equ 4 ;Set when a multiblock read is in progress
M_MBWR equ 3 ;Set when a multiblock write is in progress
;;; Variable Storage ;;;
@ -511,6 +514,7 @@ GetCommand
CmdUnknown
movf RC_CMDN,W ;Save the unknown command's number since it's
movwf TEMP2 ; about to be overwritten
;TODO log unknown commands and expected response lengths somehow
call ClearResponse ;Clear the buffer according to expectations
movf TEMP2,W ;Our reply is going to be the command number
movwf TX_CMDN ; with its MSB set, by convention, but data
@ -539,6 +543,7 @@ NakCommand
goto IdleJump ;Done
CmdRead
call MmcStopOngoing ;Stop any multiblock read or write
clrf M_BUF5 ;Shift the block address left by 9 (multiply it
lslf RC_ADRL,W ; by 512) to transform it into the byte address
movwf M_BUF4 ; used by the MMC card
@ -560,8 +565,10 @@ CmdRea0 movlw 0x02 ;Increment the read address by 512 - we do this
movlw 0 ; sector on the MMC card is the controller
addwfc M_BUF3,F ; status block, conveniently
addwfc M_BUF2,F ; "
movlw 0x51 ;Set up a read command for the MMC card
movwf M_BUF1 ; "
movlw 0x51 ;Set up a read command for the MMC card (R1-
movwf M_BUF1 ; type response)
bcf M_FLAGS,M_CMDLR ; "
bcf M_FLAGS,M_CMDRB ; "
bcf PORTC,RC3 ;Assert !CS
btfss M_FLAGS,M_FAIL ;If there haven't been any previous failures,
call MmcCmd ; send the MMC command
@ -592,6 +599,7 @@ CmdRea0 movlw 0x02 ;Increment the read address by 512 - we do this
goto IdleJump ; do, so call it done
CmdWrite
call MmcStopOngoing ;Stop any multiblock read or write
clrf M_BUF5 ;Shift the block address left by 9 (multiply it
lslf RC_ADRL,W ; by 512) to transform it into the byte address
movwf M_BUF4 ; used by the MMC card
@ -604,19 +612,26 @@ CmdWrite
movlw 0 ; sector on the MMC card is the controller
addwfc M_BUF3,F ; status block
addwfc M_BUF2,F ; "
CmdWriteCont
movlw 0x58 ;Set up a write command for the MMC card, maybe
movwf M_BUF1 ; with an address set up by a previous command
movlw 0x59 ;Set up a write command for the MMC card (R1-
movwf M_BUF1 ; type reply)
bcf M_FLAGS,M_CMDLR ; "
bcf M_FLAGS,M_CMDRB ; "
bsf M_FLAGS,M_MBWR ;Set the flag for an ongoing multiblock write
bcf PORTC,RC3 ;Assert !CS
btfss M_FLAGS,M_FAIL ;If there haven't been any previous failures,
call MmcCmd ; send the MMC command
CmdWriteCont
btfss M_FLAGS,M_MBWR ;If for some reason we got here without there
bra NakCommand ; being a multiblock write going on, NAK
movlw 0x20 ;Point FSR0 past the sync, length, header, and
movwf FSR0H ; tag bytes, and to the data we'll be writing
movlw 0x1D ; "
movwf FSR0L ; "
btfss M_FLAGS,M_FAIL ;If the operation didn't fail, write data to
call MmcWriteData ; the MMC card
bsf PORTC,RC3 ;Deassert !CS
decf RC_BLKS,W ;If the blocks-remaining counter is at one,
btfsc STATUS,Z ; stop the multiblock write here before sending
call MmcStopOngoing ; our response to the mac
movf RC_BLKS,W ;Move the block count from receiver position to
movwf TX_BLKS ; transmitter position
movlw 0x81 ;Command number is the write command with the
@ -636,20 +651,18 @@ CmdWriteCont
movlp high Transmit ;Initiate transmission
call Transmit ; "
movlp 0 ; "
movlw 0x02 ;Increment the read address by 512 in case more
addwf M_BUF4,F ; blocks are to come (with command number 0x41)
movlw 0 ; because its handler is this one, just jumped
addwfc M_BUF3,F ; into a bit late
addwfc M_BUF2,F ; "
goto IdleJump ;Done
CmdStatus
call MmcStopOngoing ;Stop any multiblock read or write
clrf M_BUF5 ;Set the address to read the first sector of
clrf M_BUF4 ; the MMC card
clrf M_BUF3 ; "
clrf M_BUF2 ; "
movlw 0x51 ;Set up a read command for the MMC card
movwf M_BUF1 ; "
movlw 0x51 ;Set up a read command for the MMC card (R1-
movwf M_BUF1 ; type reply)
bcf M_FLAGS,M_CMDLR ; "
bcf M_FLAGS,M_CMDRB ; "
movlw 0x83 ;Command number is the status command with the
movwf TX_CMDN ; MSB set
clrf TX_BLKS ;Block count is a pad byte in status command
@ -780,6 +793,7 @@ ClearR0 movwi FSR0++ ;Write seven zeroes to the buffer
;Initialize MMC card. Sets M_FAIL on fail. Trashes TEMP.
MmcInit
clrf M_FLAGS ;Make sure flags are all clear to begin with
movlb 4 ;This is where all the SSP registers are
movlw 10 ;Send 80 clocks on SPI interface to ensure MMC
movwf TEMP ; card is started up and in native command mode
@ -800,6 +814,7 @@ MmcIni0 movlw 0xFF ; "
movlw 0x95 ; "
movwf M_BUF6 ; "
bcf M_FLAGS,M_CMDLR ; "
bcf M_FLAGS,M_CMDRB ; "
call MmcCmd ; "
btfsc M_FLAGS,M_FAIL ;If this command failed, unrecognized or
return ; missing MMC card, fail the init operation
@ -817,6 +832,7 @@ MmcIni1 movlw 0x41 ;Send command 1 (expect R1-type response),
clrf M_BUF5 ; "
clrf M_BUF6 ; "
bcf M_FLAGS,M_CMDLR ; "
bcf M_FLAGS,M_CMDRB ; "
call MmcCmd ; "
btfsc M_FLAGS,M_FAIL ;If this command failed, unrecognized MMC card,
return ; fail the init operation
@ -837,6 +853,7 @@ MmcIni2 movlw 0x50 ;Send command 16 (expect R1-type response) to
clrf M_BUF5 ; "
clrf M_BUF6 ; "
bcf M_FLAGS,M_CMDLR ; "
bcf M_FLAGS,M_CMDRB ; "
call MmcCmd ; "
btfsc M_FLAGS,M_FAIL ;If this command failed, something is wrong,
return ; fail the init operation
@ -892,16 +909,18 @@ MmcRea3 movlw 0xFF ;Clock the next data byte out of the MMC card
return
;Write 512 bytes of data to MMC card from buffer pointed to by FSR0. Sets
; M_FAIL on fail. Trashes TEMP and FSR0.
; M_FAIL on fail. Trashes TEMP, TEMP2, and FSR0.
MmcWriteData
movlb 4 ;Switch to the bank with the SSP registers
movlw 0xFF ;Clock a dummy byte while keeping MOSI high
movwf SSP1BUF ; "
btfss SSP1STAT,BF ; "
bra $-1 ; "
movlw 0xFE ;Clock the data token into the MMC card
movwf SSP1BUF ; "
btfss SSP1STAT,BF ; "
movlw 0xFE ;Clock the data token into the MMC card (note
btfsc M_FLAGS,M_MBWR ; that CMD25, multi-block write, requires a
movlw 0xFC ; different token than CMD24, single-block
movwf SSP1BUF ; write, so we differentiate based on the flag
btfss SSP1STAT,BF ; for ongoing multi-block write)
bra $-1 ; "
clrf TEMP ;Send 256 pairs of bytes
MmcWri0 moviw FSR0++ ;Clock the next data byte into the MMC card
@ -928,22 +947,46 @@ MmcWri0 moviw FSR0++ ;Clock the next data byte into the MMC card
andlw B'00011111' ; was rejected for any reason, fail the write
xorlw B'00000101' ; operation
btfss STATUS,Z ; "
bra MmcWri2 ; "
clrf TEMP ;Check 65536 times to see if the write is done
clrf TEMP2 ; "
MmcWri1 movlw 0xFF ;Clock a byte out of the MMC card while keeping
movwf SSP1BUF ; MOSI high
bsf M_FLAGS,M_FAIL ; "
btfss M_FLAGS,M_FAIL ;If we didn't fail, wait for the card not to be
call MmcWaitBusy ; busy anymore
movlb 0 ;Return to the default bank
return
;Stop a multiblock read or write, if one is ongoing, and deassert !CS. Sets
; M_FAIL on fail. Trashes TEMP and TEMP2.
MmcStopOngoing
btfsc M_FLAGS,M_FAIL ;If there's a fail on the MMC card, return
return ; immediately
btfsc M_FLAGS,M_MBWR ;If there's an ongoing write operation, make it
bra MmcSto0 ; stop
btfss M_FLAGS,M_MBRD ;If there's not an ongoing read operation, this
return ; function was called needlessly, return
movlw 0x4C ;Send a CMD12 to stop the ongoing read, R1b
movwf M_BUF1 ; reply type
clrf M_BUF2 ; "
clrf M_BUF3 ; "
clrf M_BUF4 ; "
clrf M_BUF5 ; "
bcf M_FLAGS,M_CMDLR ; "
bsf M_FLAGS,M_CMDRB ; "
call MmcCmd ; "
bcf M_FLAGS,M_MBRD ;Clear the ongoing multiblock read flag
bsf PORTC,RC3 ;Deassert !CS
return
MmcSto0 movlb 4 ;Switch to the bank with the SSP registers
movlw 0xFD ;Clock the end-of-data token into the MMC card
movwf SSP1BUF ; "
btfss SSP1STAT,BF ; "
bra $-1 ; "
movf SSP1BUF,W ;Check if MISO is still low, if it's not, the
btfss STATUS,Z ; write is done and we can return
bra MmcWri3 ; "
decfsz TEMP,F ;If it's not done, try again
bra MmcWri1 ; "
decfsz TEMP2,F ; "
bra MmcWri1 ; "
MmcWri2 bsf M_FLAGS,M_FAIL ;If out of tries, fail the write operation
MmcWri3 movlb 0 ;Return to the default bank
movlw 0xFF ;Clock a dummy byte while keeping MOSI high
movwf SSP1BUF ; "
btfss SSP1STAT,BF ; "
bra $-1 ; "
call MmcWaitBusy ;Wait for the card to not be busy anymore
movlb 0 ;Return to the default bank
bcf M_FLAGS,M_MBWR ;Clear the ongoing multiblock write flag
bsf PORTC,RC3 ;Deassert !CS
return
;Send the command contained in M_BUF1-6 to MMC card. Sets M_FAIL on fail.
@ -1017,9 +1060,28 @@ MmcCmd2 decf WREG,W ;Store the byte we received as R1-type status
bra $-1 ; "
movf SSP1BUF,W ; "
movwf M_BUF5 ; "
MmcCmd3 ;TODO microchip's code sends another 8 clocks here but I can't find
; anything in the spec that says we have to do that
movlb 0
MmcCmd3 btfsc M_FLAGS,M_CMDRB ;If we're expecting an R1b reply, wait for the
call MmcWaitBusy ; card not to be busy anymore before returning
movlb 0 ;Restore BSR to 0
return
;Waits for the card not to be busy anymore. Sets M_FAIL on fail. Trashes TEMP
; and TEMP2. Expects BSR to be 4 and does not set or reset this.
MmcWaitBusy
clrf TEMP ;Check 65536 times to see if the card is busy
clrf TEMP2 ; "
MmcWai0 movlw 0xFF ;Clock a byte out of the MMC card while keeping
movwf SSP1BUF ; MOSI high
btfss SSP1STAT,BF ; "
bra $-1 ; "
movf SSP1BUF,W ;Check if MISO is still low, if it's not, the
btfss STATUS,Z ; card is no longer busy and we can return
return ; "
decfsz TEMP,F ;If it's not done, try again
bra MmcWai0 ; "
decfsz TEMP2,F ; "
bra MmcWai0 ; "
bsf M_FLAGS,M_FAIL ;If out of tries, fail the operation
return