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https://github.com/lampmerchant/tashtwenty.git
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20220424
This commit is contained in:
lampmerchant
parent
70cf1e5b88
commit
a49b5b2f1e
@ -90,8 +90,8 @@ IWMCNT0 equ 0 ; "
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M_FAIL equ 7 ;Set when there's been a failure on the MMC interface
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M_CMDLR equ 6 ;Set when R3 or R7 is expected (5 bytes), not R1
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M_CMDRB equ 5 ;Set when an R1b is expected (busy signal after reply)
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M_MBRD equ 4 ;Set when a multiblock read is in progress
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M_MBWR equ 3 ;Set when a multiblock write is in progress
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M_RDCMD equ 4 ;Set when state machine should do a read command
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M_ONGWR equ 3 ;Set when state machine shouldn't stop tran on a write
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M_BKADR equ 2 ;Set when block (rather than byte) addressing is in use
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M_CDVER equ 1 ;Set when dealing with a V2.0+ card, clear for 1.0
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@ -127,7 +127,7 @@ M_CDVER equ 1 ;Set when dealing with a V2.0+ card, clear for 1.0
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M_ADR0 ;Fourth (low) byte of the address, last byte of R3/R7 response
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M_CRCH ;CRC16 high byte
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M_CRCL ;CRC16 low byte
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X6 ;Various purposes
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M_STATE ;State of card state machine
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X5 ;Various purposes
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X4 ;Various purposes
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X3 ;Various purposes
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@ -526,11 +526,9 @@ Unselected
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tris 7 ; done this already, but.. belt and suspenders)
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movlb 3 ;Deassert !HSHK
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clrf TXREG ; "
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movlb 0 ;Deassert !CS and next !ENBL (the interrupt
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movlw B'00111111' ; handler will have deasserted next !ENBL
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movwf PORTC ; already, but.. belt and suspenders)
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movlw B'00111111' ; "
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movwf PORTA ; "
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movlb 0 ;Deassert next !ENBL (the interrupt handler
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movlw B'00111111' ; will have deasserted next !ENBL already,
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movwf PORTA ; but.. belt and suspenders)
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clrf DEVNUM ;Reset selected device number to zero
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btfsc EN_PORT,EN_PIN ;Wait for Mac to drive !ENBL low
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bra $-1 ; "
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@ -862,6 +860,16 @@ SysIni6 addfsr FSR0,16 ;Move pop pointer ahead to next entry
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;;; Receiver ;;;
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Receiver
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movlw 4 ;Spend about 262.144 ms waiting for the state
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movwf X1 ; machine to try and get the card back to
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Receiv0 clrf TMR1H ; waiting for a command or a write token, which
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clrf TMR1L ; is about how long we have before Mac tires of
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movlw MSSWrEtTok - MSS; waiting for us to acknowledge a command (we
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btfss M_FLAGS,M_ONGWR ; actually have ~350 ms, but be cautious);
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movlw MSSWaitCmd - MSS; hopefully this will be enough, spec says that
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call MmcWaitState ; writes may take up to 200 ms
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decfsz X1,F ; "
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bra Receiv0 ; "
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movlb 3 ;Assert !HSHK to signal to Mac that we're
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btfss TXSTA,TRMT ; ready to receive
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bra $-1 ; "
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@ -1022,25 +1030,22 @@ BadChk1 movlp 0 ;Return to the idle loop
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goto IdleLoop ; "
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CmdRead
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call MmcStopOngoing ;Make sure any ongoing write is stopped
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movlw ERRCODE ;Ready an error code in case we need to jump
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movwf RESPERR ; into the placeholder response routine
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call SetupCmdAddr ;Set up the card address for this command
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btfsc STATUS,C ;If the read is out of bounds, send an error
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goto CmdPlaceholder ; response
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CmdRea0 movlw 0x51 ;Set up a read command for the card (R1-type
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movwf M_CMDN ; response)
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bcf M_FLAGS,M_CMDLR ; "
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bcf M_FLAGS,M_CMDRB ; "
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bcf CS_PORT,CS_PIN ;Assert !CS
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call MmcCmd ;Send the read command
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movf M_CMDN,W ;Treat any error flag as a failed command
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andlw B'11111110' ; "
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btfss STATUS,Z ; "
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bsf M_FLAGS,M_FAIL ; "
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btfss M_FLAGS,M_FAIL ;If no failures up to this point, prepare the
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call MmcGetData ; card to read out data
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btfsc M_FLAGS,M_FAIL ;If there was any failure, respond with a
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CmdRea0 bsf M_FLAGS,M_RDCMD ;Set the state machine to do a read for us
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bcf M_FLAGS,M_ONGWR ;Cancel any ongoing write
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movlw 4 ;Spend about 262.144 ms waiting for the state
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movwf X1 ; machine to prepare the card to read out the
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CmdRea5 clrf TMR1H ; data, which is about how long we have before
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clrf TMR1L ; Mac tires of waiting for a response from us
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movlw MSSRdData - MSS ; (we actually have ~350 ms, but be cautious)
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call MmcWaitState ; "
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decfsz X1,F ; "
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bra CmdRea5 ; "
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btfsc PIR1,TMR1IF ;If there was any failure, respond with a
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goto CmdPlaceholder ; placeholder with an error code
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clrf M_CRCH ;Clear the CRC registers for our read of the
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clrf M_CRCL ; block
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@ -1082,6 +1087,8 @@ CmdRea2 moviw FSR0++ ;Pick up the next byte to write from the queue
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bra CmdRea2 ; "
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decfsz X3,F ; "
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bra CmdRea2 ; "
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movlw MSSWaitCmd - MSS;Finished with read, so set state back to
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movwf M_STATE ; WaitCmd
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movf M_CRCH,W ;Feeding the CRC through the CRC registers
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iorwf M_CRCL,W ; should leave it at zero if the CRC is right;
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btfss STATUS,Z ; if it's not, send the wrong checksum so Mac
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@ -1104,7 +1111,6 @@ CmdRea4 comf CHKSUM,W ;CRC failed, so write what we know is the wrong
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bra CmdRea3
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CmdStatus
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call MmcStopOngoing ;Make sure any ongoing write is stopped
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movlw 0x21 ;Point to the partition information block for
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movwf FSR0H ; the selected device
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swapf DEVNUM,W ; "
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@ -1115,26 +1121,24 @@ CmdStatus
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xorlw 0xAF ; built-in icon, not one loaded from the card,
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btfsc STATUS,Z ; so skip setting up the read
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bra CmdSta0 ; "
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movlw 0x51 ;Set up a read command for the card (R1-type
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movwf M_CMDN ; response)
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bcf M_FLAGS,M_CMDLR ; "
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bcf M_FLAGS,M_CMDRB ; "
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bsf M_FLAGS,M_RDCMD ;Set the state machine to do a read for us
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bcf M_FLAGS,M_ONGWR ;Cancel any ongoing write
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clrf M_ADR3 ;Point to the address of the icon to be loaded
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clrf M_ADR2 ; "
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clrf M_ADR1 ; "
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moviw 4[FSR0] ; "
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movwf M_ADR0 ; "
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bcf CS_PORT,CS_PIN ;Assert !CS
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call MmcConvAddr ;Convert address to bytes if necessary
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btfss M_FLAGS,M_FAIL ;If the address conversion didn't fail, send
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call MmcCmd ; the read command
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movf M_CMDN,W ;Treat any error flag as a failed command
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andlw B'11111110' ; "
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btfss STATUS,Z ; "
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bsf M_FLAGS,M_FAIL ; "
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btfsc M_FLAGS,M_FAIL ;If the operation failed, use the built-in icon
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bra CmdSta0 ; instead
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call MmcGetData ;Get the card ready to read out data
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movlw 4 ;Spend about 262.144 ms waiting for the state
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movwf X1 ; machine to prepare the card to read out the
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CmdSta8 clrf TMR1H ; icon, which is about how long we have before
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clrf TMR1L ; Mac tires of waiting for a response from us
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movlw MSSRdData - MSS ; (we actually have ~350 ms, but be cautious)
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call MmcWaitState ; "
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decfsz X1,F ; "
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bra CmdSta8 ; "
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btfsc PIR1,TMR1IF ;If it timed out, use the built in icon instead
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bra CmdSta0 ; "
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movlw 0x22 ;Point the push pointer off into space and
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movwf FSR1H ; read and throw away the first 256 bytes of
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movlw 0 ; the icon sector
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@ -1187,7 +1191,7 @@ CmdSta3 movlw 0 ; area (52 bytes), all as zeroes
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moviw 4[FSR0] ;If the partition type is 0xAF or we had a fail
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xorlw 0xAF ; while reading from the card, we're using the
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btfss STATUS,Z ; built-in icon, so skip ahead to do that
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btfsc M_FLAGS,M_FAIL ; "
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btfsc PIR1,TMR1IF ; "
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bra CmdSta4 ; "
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movlw 0 ;Copy 256 bytes from the card to the Mac
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call MmcCopyData ; "
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@ -1232,8 +1236,12 @@ CmdSta7 movlw 0 ; area (52 bytes), all as zeroes
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movf CHKSUM,W ;Finish the block off with the checksum
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call WriteByte ; "
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btfss X2,0 ;If we didn't use the built-in icon, finish up
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call MmcCheckCrc ; with the card by ignoring the CRC
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bsf CS_PORT,CS_PIN ;Deassert !CS
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call MmcCheckCrc ; with the card by ignoring the CRC and setting
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movlw MSSWaitCmd - MSS; the state back to WaitCmd and deasserting !CS
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btfss X2,0 ; "
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movwf M_STATE ; "
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btfss X2,0 ; "
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bsf CS_PORT,CS_PIN ; "
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call ReturnToIdle ;Return to the idle state
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movlp 0 ;Return to the idle loop
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goto IdleLoop ; "
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@ -1244,8 +1252,12 @@ CmdWrite
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call SetupCmdAddr ;Set up the card address for this command
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btfsc STATUS,C ;If the write is out of bounds, send an error
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goto WaitToFinish ; response after we've received the command
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btfsc M_FLAGS,M_MBWR ;If we're starting a new write even though a
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bra CmdWri7 ; multiblock write is ongoing, handle it
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movf M_STATE,W ;If we're not in the await-command state, we
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xorlw MSSWaitCmd - MSS; won't be able to do this write, so send an
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btfss STATUS,Z ; error response
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goto WaitToFinish ; "
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btfsc M_FLAGS,M_ONGWR ;If we're starting a new write even though a
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bra CmdWri6 ; multiblock write is ongoing, handle it
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movlw 0x59 ;Set up a multiblock write command for the card
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movwf M_CMDN ; (R1-type reply)
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bcf M_FLAGS,M_CMDLR ; "
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@ -1258,7 +1270,7 @@ CmdWrite
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bsf M_FLAGS,M_FAIL ; "
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btfsc M_FLAGS,M_FAIL ;If there was any failure, respond with a
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goto WaitToFinish ; placeholder with an error code
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bsf M_FLAGS,M_MBWR ;Flag that a multiblock write is in progress
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bsf M_FLAGS,M_ONGWR ;Flag that a multiblock write is in progress
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CmdWri0 movlb 4 ;Clock a dummy byte while keeping MOSI high
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movlw 0xFF ; "
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movwf SSP1BUF ; "
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@ -1339,37 +1351,54 @@ CmdWri4 movlb 4 ;Clock the byte out to the card
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bra $-1 ; "
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movf SSP1BUF,W ;Save data response to check later
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movwf X2 ; "
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call MmcWaitBusy ;Wait for the card not to be busy anymore
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movlb 0 ;If the data response byte indicated that the
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movf X2,W ; write succeeded, skip ahead
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movlw 0xFF ;Start clocking the first is-still-busy? byte
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movwf SSP1BUF ; "
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movlb 0 ; "
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bcf PIR1,SSP1IF ;Clear SSP int flag so it knows when not busy
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movlw MSSWrBusy - MSS ;Set the card state to WrBusy so state machine
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movwf M_STATE ; knows
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decf CMDCNT,W ;If this was the last block, clear the ongoing
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btfsc STATUS,Z ; write flag so state machine knows not to stop
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bcf M_FLAGS,M_ONGWR ; waiting on a write or stop tran token
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movf X2,W ;Check if the write succeeded
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andlw B'00011111' ; "
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xorlw B'00000101' ; "
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btfsc STATUS,Z ; "
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bra CmdWri6 ; "
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CmdWri5 call MmcStopOngoing ;Stop the ongoing write
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btfss IWMFLAG,IWMOVER ;Wait until the Mac's transmission is over
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btfsc STATUS,Z ;If it did, clear the error flag so we send a
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clrf RESPERR ; success response
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btfss STATUS,Z ;If it didn't, clear the ongoing write flag so
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bcf M_FLAGS,M_ONGWR ; the write ends here
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CmdWri5 btfss IWMFLAG,IWMOVER ;Wait until the Mac's transmission is over
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bra $-1 ; "
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call ReturnToIdle ;If the checksum was wrong, send a NAK, if it
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movf CHKSUM,W ; was right, send an error
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btfss STATUS,Z ; "
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goto BadChecksum ; "
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movf CHKSUM,W ;If the checksum didn't match, clear the
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btfss STATUS,Z ; ongoing write flag because the write stops
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bcf M_FLAGS,M_ONGWR ; here
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clrf TMR1H ;Spend about 65.536 ms, which is about how long
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clrf TMR1L ; we have before Mac timeouts waiting for us to
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movlw MSSWrEtTok - MSS; return to idle, waiting for the state machine
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btfss M_FLAGS,M_ONGWR ; to try and get the card back to waiting for
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movlw MSSWaitCmd - MSS; a command or a write token (we actually have
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call MmcWaitState ; ~90 ms, but let's be cautious)
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call ReturnToIdle ;That's long enough, return us to idle
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movf CHKSUM,W ;If the checksum was wrong, send a NAK, else
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btfss STATUS,Z ; send either a failure or success depending
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goto BadChecksum ; on RESPERR
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goto CmdPlaceholder ; "
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CmdWri6 decf CMDCNT,W ;If this was the last block in the write, stop
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btfsc STATUS,Z ; the ongoing write
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call MmcStopOngoing ; "
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clrf RESPERR ;Send a success response
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call ReturnToIdle ; "
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goto CmdPlaceholder ; "
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CmdWri7 movlw 1 ;In the unlikely event Mac tried to start a new
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CmdWri6 movlw 1 ;In the unlikely event Mac tried to start a new
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movwf CHKSUM ; write while one was ongoing, pretend there
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bra CmdWri5 ; was a bad checksum so it tries again
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CmdWriteCont
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movlw ERRCODE ;Ready an error code in case we need to jump
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movwf RESPERR ; into the placeholder response routine
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btfsc M_FLAGS,M_MBWR ;If a multibyte write is already ongoing, as it
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bra CmdWri0 ; should be, jump into the middle of CmdWrite,
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goto WaitToFinish ; otherwise send an error response
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btfss M_FLAGS,M_ONGWR ;If a write isn't ongoing as it should be,
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bra CmdWrC0 ; handle this
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movf M_STATE,W ;If we're not in the await-token state, we
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xorlw MSSWrEtTok - MSS; won't be able to do this write, handle this
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btfss STATUS,Z ; "
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bra CmdWrC0 ; "
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bra CmdWri0 ;Else jump into the middle of CmdWrite
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CmdWrC0 bcf M_FLAGS,M_ONGWR ;If something went wrong, end the ongoing write
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goto WaitToFinish ; and send an error response
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;;; Subprograms ;;;
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@ -1398,21 +1427,21 @@ SetupCmdAddr
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movlw 0 ; "
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addwfc CMDHIGH,W ; "
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movwf M_ADR2 ; "
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moviw 5[FSR0] ;If the partition size is less than or equal to
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moviw 7[FSR0] ;If the partition size is less than or equal to
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subwf M_ADR0,W ; the maximum block number accessed, return
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moviw 6[FSR0] ; with carry set
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subwfb M_ADR1,W ; "
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moviw 7[FSR0] ; "
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moviw 5[FSR0] ; "
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subwfb M_ADR2,W ; "
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btfsc STATUS,C ; "
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bra SetCmA0 ; "
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movf INDF0,W ;Move the starting block of the partition into
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movwf M_ADR3 ; the card address registers
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moviw 1[INDF0] ; "
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moviw 1[FSR0] ; "
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movwf M_ADR2 ; "
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moviw 2[INDF0] ; "
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moviw 2[FSR0] ; "
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movwf M_ADR1 ; "
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moviw 3[INDF0] ; "
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moviw 3[FSR0] ; "
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addwf CMDLOW,W ;Add the block address from the command to it
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movwf M_ADR0 ; "
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movf CMDMED,W ; "
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@ -1587,6 +1616,7 @@ ReqSnd1 bsf STATUS,Z ;We've successfully requested to send, set the
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;Initialize MMC card. Sets M_FAIL on fail. Trashes X0 through X3.
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MmcInit
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clrf M_FLAGS ;Make sure flags are all clear to begin with
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clrf M_STATE ;Make sure state starts at awaiting command
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call MmcIni0 ;Call into the function below
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bsf CS_PORT,CS_PIN ;Always deassert !CS
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movf WREG,W ;If the init function returned a code other
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@ -2055,40 +2085,206 @@ MmcChe0 movlw 0xFF ;Clock the low CRC byte out of the card
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movlb 0 ; return
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return ; "
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;Stop a multiblock read or write, if one is ongoing, and deassert !CS. Sets
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; M_FAIL on fail. Trashes X0 and X1.
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MmcStopOngoing
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bcf M_FLAGS,M_FAIL ;Assume no failure to start with
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btfsc M_FLAGS,M_MBWR ;If there's an ongoing write operation, make it
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bra MmcSto0 ; stop
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btfss M_FLAGS,M_MBRD ;If there's not an ongoing read operation, this
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return ; function was called needlessly, return
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movlw 0x4C ;Send a CMD12 to stop the ongoing read, R1b
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movwf M_CMDN ; reply type
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clrf M_ADR3 ; "
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clrf M_ADR2 ; "
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clrf M_ADR1 ; "
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clrf M_ADR0 ; "
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bcf M_FLAGS,M_CMDLR ; "
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bsf M_FLAGS,M_CMDRB ; "
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call MmcCmd ; "
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bcf M_FLAGS,M_MBRD ;Clear the ongoing multiblock read flag
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bsf CS_PORT,CS_PIN ;Deassert !CS
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return
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MmcSto0 movlb 4 ;Switch to the bank with the SSP registers
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movlw 0xFD ;Clock the end-of-data token into the MMC card
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;Try to advance to the state requested in W, timing out if Timer1 overflows.
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; Trashes X0.
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MmcWaitState
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movwf X0 ;Save the state caller wants to get to
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movlw B'00110001' ;Turn on Timer1
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movwf T1CON ; "
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bcf PIR1,TMR1IF ;Clear the Timer1 interrupt flag if it was set
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movf M_STATE,W ;If we're already in the state caller wants to
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xorwf X0,W ; be in, skip ahead
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btfsc STATUS,Z ; "
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bra MmcWaS1 ; "
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MmcWaS0 call MmcStepState ;Step the state
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movf M_STATE,W ;If we're now in the state caller wants to be
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xorwf X0,W ; in, skip ahead
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btfsc STATUS,Z ; "
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bra MmcWaS1 ; "
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btfsc PIR1,TMR1IF ;If Timer1 overflowed, skip ahead
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bra MmcWaS2 ; "
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bra MmcWaS0 ;Loop until something happens
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MmcWaS1 bcf T1CON,TMR1ON ;Stop Timer1 and clear its interrupt flag so
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bcf PIR1,TMR1IF ; caller knows we're in the state requested and
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return ; did not time out
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MmcWaS2 bcf T1CON,TMR1ON ;Stop Timer1 and leave its interrupt flag set
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return ; so caller knows a timeout occurred
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;State machine to ensure that the card stays in a good state.
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MmcStepState
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btfss PIR1,SSP1IF ;If the SSP is busy, we can't do anything, so
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return ; return
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||||
movlb 4 ;Switch depending on the current state
|
||||
movf M_STATE,W ; "
|
||||
call MSSCall ; "
|
||||
movwf M_STATE ;Save the returned value in W as the new state
|
||||
movlb 0 ; and return
|
||||
movlp 8 ; "
|
||||
return ; "
|
||||
MSSCall brw
|
||||
MSS
|
||||
MSSWaitCmd
|
||||
btfss M_FLAGS,M_RDCMD ;If we're not set to do a read command, cycle
|
||||
retlw MSSWaitCmd - MSS; back to this state doing nothing
|
||||
movlb 0 ;Assert !CS
|
||||
bcf CS_PORT,CS_PIN ; "
|
||||
movlb 4 ; "
|
||||
movlw 0x51 ;Clock out the command byte for a read
|
||||
movwf SSP1BUF ; "
|
||||
btfss SSP1STAT,BF ; "
|
||||
bra $-1 ; "
|
||||
movlw 0xFF ;Clock a dummy byte while keeping MOSI high
|
||||
movlw 0xE8 ;Set up the CRC register with the CRC7 of the
|
||||
movwf M_CRCL ; read command byte
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSRdCmd1 - MSS ;Transition to the next read command state
|
||||
MSSRdCmd1
|
||||
movf M_ADR3,W ;Clock out the high byte of the address
|
||||
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 CS_PORT,CS_PIN ;Deassert !CS
|
||||
return
|
||||
movlp high LutCrc7 ;Update the CRC for the command
|
||||
xorwf M_CRCL,W ; "
|
||||
callw ; "
|
||||
movwf M_CRCL ; "
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSRdCmd2 - MSS ;Transition to the next read command state
|
||||
MSSRdCmd2
|
||||
movf M_ADR2,W ;Clock out the next byte of the address
|
||||
movwf SSP1BUF ; "
|
||||
movlp high LutCrc7 ;Update the CRC for the command
|
||||
xorwf M_CRCL,W ; "
|
||||
callw ; "
|
||||
movwf M_CRCL ; "
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSRdCmd3 - MSS ;Transition to the next read command state
|
||||
MSSRdCmd3
|
||||
movf M_ADR1,W ;Clock out the next byte of the address
|
||||
movwf SSP1BUF ; "
|
||||
movlp high LutCrc7 ;Update the CRC for the command
|
||||
xorwf M_CRCL,W ; "
|
||||
callw ; "
|
||||
movwf M_CRCL ; "
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSRdCmd4 - MSS ;Transition to the next read command state
|
||||
MSSRdCmd4
|
||||
movf M_ADR0,W ;Clock out the low byte of the address
|
||||
movwf SSP1BUF ; "
|
||||
movlp high LutCrc7 ;Update the CRC for the command
|
||||
xorwf M_CRCL,W ; "
|
||||
callw ; "
|
||||
movwf M_CRCL ; "
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSRdCmd5 - MSS ;Transition to the next read command state
|
||||
MSSRdCmd5
|
||||
movf M_CRCL,W ;Clock out the CRC for the command
|
||||
movwf SSP1BUF ; "
|
||||
bcf M_FLAGS,M_RDCMD ;Read command complete, M_ADR* are free
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSRdCmd6 - MSS ;Transition to the next read command state
|
||||
MSSRdCmd6
|
||||
movlw 0xFF ;Clock first is-still-busy? byte out of the
|
||||
movwf SSP1BUF ; card
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSRdCmd7 - MSS ; "
|
||||
MSSRdCmd7
|
||||
btfss SSP1BUF,7 ;If MSB is set, this isn't an R1 response byte,
|
||||
bra $+6 ; so clock out another byte and try again
|
||||
movlw 0xFF ; "
|
||||
movwf SSP1BUF ; "
|
||||
movlb 0 ; "
|
||||
bcf PIR1,SSP1IF ; "
|
||||
retlw MSSRdCmd7 - MSS ; "
|
||||
movf SSP1BUF,W ;If MSB is clear but an error bit is set, the
|
||||
andlw B'11111110' ; command was not processed, so go back to the
|
||||
btfsc STATUS,Z ; WaitCmd state after deasserting !CS
|
||||
bra $+4 ; "
|
||||
movlb 0 ; "
|
||||
bsf CS_PORT,CS_PIN ; "
|
||||
retlw MSSWaitCmd - MSS; "
|
||||
movlw 0xFF ;If all error bits are clear in the response
|
||||
movwf SSP1BUF ; byte, clock out the first is-read-token? byte
|
||||
movlb 0 ; "
|
||||
bcf PIR1,SSP1IF ; "
|
||||
retlw MSSRdTok - MSS ; "
|
||||
MSSRdTok
|
||||
movf SSP1BUF,W ;Check if the byte read from the card is the
|
||||
xorlw 0xFE ; read token
|
||||
btfsc STATUS,Z ;If the byte read was not the read token, start
|
||||
bra $+6 ; the next byte clocking out and remain in this
|
||||
movlw 0xFF ; state for next call
|
||||
movwf SSP1BUF ; "
|
||||
movlb 0 ; "
|
||||
bcf PIR1,SSP1IF ; "
|
||||
retlw MSSRdTok - MSS ; "
|
||||
movlw 0xFD ;If byte read was the read token, transition
|
||||
movwf M_CRCH ; to RdData using CRC register as an up counter
|
||||
movwf M_CRCL ; set to -515 (512 bytes + 2 CRC bytes + 1),
|
||||
retlw MSSRdData - MSS ; assuming we have to throw away the read data
|
||||
MSSRdData
|
||||
incf M_CRCL,F ;Step the up counter
|
||||
btfsc STATUS,Z ; "
|
||||
incf M_CRCH,F ; "
|
||||
btfss STATUS,Z ;If the up counter overflowed, deassert !CS
|
||||
bra $+4 ; and reset the state to WaitCmd without
|
||||
movlb 0 ; starting a byte clocking
|
||||
bsf CS_PORT,CS_PIN ; "
|
||||
retlw MSSWaitCmd - MSS; "
|
||||
movlw 0xFF ;Start the next byte to read clocking out and
|
||||
movwf SSP1BUF ; stay in this state for next time
|
||||
movlb 0 ; "
|
||||
bcf PIR1,SSP1IF ; "
|
||||
retlw MSSRdData - MSS ; "
|
||||
MSSWrEtTok
|
||||
btfsc M_FLAGS,M_ONGWR ;If there's an ongoing write, don't proceed in
|
||||
retlw MSSWrEtTok - MSS; sending an end tran token
|
||||
movlw 0xFD ;Start an end tran token clocking
|
||||
movwf SSP1BUF ; "
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSEtJnk1 - MSS ;Transition to EtJnk1
|
||||
MSSEtJnk1
|
||||
movlw 0xFF ;Byte we got in when we clocked out the end
|
||||
movwf SSP1BUF ; tran token is junk, so is the next one
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSEtJnk2 - MSS ;Transition to EtJnk2
|
||||
MSSEtJnk2
|
||||
movlw 0xFF ;Byte we got in from previous state is junk,
|
||||
movwf SSP1BUF ; the one we're clocking now is legit
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSEtBusy - MSS ;Transition to EtBusy
|
||||
MSSEtBusy
|
||||
movf SSP1BUF,W ;If the byte we read out of the card is not all
|
||||
btfsc STATUS,Z ; zeroes, deassert !CS and transition to
|
||||
bra $+4 ; WaitCmd
|
||||
movlb 0 ; "
|
||||
bsf CS_PORT,CS_PIN ; "
|
||||
retlw MSSWaitCmd - MSS; "
|
||||
movlw 0xFF ;If the byte we read out of the card is all
|
||||
movwf SSP1BUF ; zeroes, clock the next one out while keeping
|
||||
movlb 0 ; MOSI high and stay in this state
|
||||
bcf PIR1,SSP1IF ; "
|
||||
retlw MSSEtBusy - MSS ; "
|
||||
MSSWrBusy
|
||||
movf SSP1BUF,W ;If the byte clocked in is 0x00, clock another
|
||||
btfss STATUS,Z ; byte out and return to this state
|
||||
bra $+6 ; "
|
||||
movlw 0xFF ; "
|
||||
movwf SSP1BUF ; "
|
||||
movlb 0 ; "
|
||||
bcf PIR1,SSP1IF ; "
|
||||
retlw MSSWrBusy - MSS ; "
|
||||
btfsc M_FLAGS,M_ONGWR ;If there's an ongoing write, transition to let
|
||||
retlw MSSWrEtTok - MSS; the caller send a data token if it wants to
|
||||
movlw 0xFD ;Else, start an end tran token clocking
|
||||
movwf SSP1BUF ; "
|
||||
movlb 0 ;Clear the SSP interrupt flag because it's in
|
||||
bcf PIR1,SSP1IF ; use now
|
||||
retlw MSSEtJnk1 - MSS ;Transition to EtJnk1
|
||||
|
||||
|
||||
;;; End of Program ;;;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user