LIST P=16F687, R=DEC, ST=OFF, MM=OFF INCLUDE "p16F687.inc" __CONFIG _FCMEN_OFF & _IESO_OFF & _BOR_OFF & _CP_OFF & _CPD_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _HS_OSC #define BAUD 9600 ; baud rate #define XTAL 20 ; crystal freq in MHz #define X ((XTAL*1000000)/(BAUD*64))-1 #define CS PORTC,6 ; chip select pin #define SDI TRISB^0x80,4 ; SDI pin #define SDO TRISC^0x80,7 ; SDO pin #define SCL TRISB^0x80,6 ; SCL pin ; Data segment CBLOCK 0x20 ind, msgNo, temp, cnt:2 ; local variables cmd ; MMC command code arg:4 ; MMC command argument resp ; MMC response fat:2, dir:2, dat:2 ; sectors of FAT16 file system cluster:2, fileLen:4 ; starting cluster of file and its length bytes2Skip:2 ; counter of # of bytes to skip skipCnt:4 ; local skip counter currDirSectNo ; current dir sector number (at most 31) partType, sectPerClust ; sectorSize ENDC ; Code segment ORG 0 goto main ORG 4 retfie msg1 movf ind, w addwf PCL, f dt 13, 10, 13, 10, "UART module is running", 13, 10, 0 msg2 movf ind, w addwf PCL, f dt "MMC module is active", 13, 10, 0 msg3 movf ind, w addwf PCL, f dt " CMD0 is through", 13, 10, 0 msg4 movf ind, w addwf PCL, f dt " CMD1 is through", 13, 10, 0 msg5 movf ind, w addwf PCL, f dt " MMC error", 13, 10, 0 msg6 movf ind, w addwf PCL, f dt " command accepted ", 13, 10, 0 bin2hex andlw 0x0F addwf PCL, f retlw '0' retlw '1' retlw '2' retlw '3' retlw '4' retlw '5' retlw '6' retlw '7' retlw '8' retlw '9' retlw 'A' retlw 'B' retlw 'C' retlw 'D' retlw 'E' retlw 'F' printByte ; send a byte in WREG to UART in HEX movwf temp ; and a space after it swapf temp, f movf temp, w call bin2hex call sendChar swapf temp, f movf temp, w call bin2hex call sendChar movlw 32 call sendChar return newline ; start a new line on remote terminal movlw 13 call sendChar movlw 10 call sendChar return getNextChar ; aux. procedure for getting next char movf msgNo, w ; of the message string with number in addwf PCL, f ; msgNo return goto msg1 goto msg2 goto msg3 goto msg4 goto msg5 goto msg6 goto msg7 goto msg8 goto msg9 sendChar ; send char in WREG over UART btfss PIR1, TXIF ; TX buffer is full? goto $-1 ; YES - wait movwf TXREG ; send out byte return sendString ; outputs string with number in WREG movwf msgNo ; set message number clrf ind ; start the message movf ind, w ; next char index call getNextChar ; get next char addlw 0 ; set bit Z in STATUS btfsc STATUS, Z ; end of string? return ; YES - return call sendChar incf ind, f ; get to the next char goto sendString+2 return spi_io ; send/receive byte via SPI movwf SSPBUF ; put data to send in WREG into SSPBUF btfss SSPCON, WCOL ; data sent? goto $+3 ; YES - proceed bcf SSPCON, WCOL ; NO - reset WCOL and try again goto $-4 bsf STATUS, RP0 ; switch to BANK 1 btfss SSPSTAT ^ 0x80, BF ; buffer full? goto $-1 ; NO - wait bcf STATUS, RP0 ; back to BANK 0 movf SSPBUF, w ; return the received data in WREG return composeByteAddr movlw 9 movwf temp ; multiply the sector # by 512 bcf STATUS, C ; to get the byte address rlf arg, f rlf arg+1, f rlf arg+2, f rlf arg+3, f decfsz temp, f goto $-6 return sendMMC ; send 48-bit MMC instruction movlw 0xFF ; sending of this byte not formally documented call spi_io ; but it does not work without it movf cmd, w ; send the command byte call spi_io movf arg+3, w ; send 4 argument bytes call spi_io movf arg+2, w call spi_io movf arg+1, w call spi_io movf arg, w call spi_io movlw 0x40 ; setup CRC7: it is 0xFF for all instructions subwf cmd, w ; except CMD0, for which it must be 0x95 movlw 0xFF btfsc STATUS, Z movlw 0x95 call spi_io movlw 0x41 ; setup waiting time: it is 80 cycles for subwf cmd, w ; all instructions except of CMD1, for movlw 255 ; which it must be 2 btfsc STATUS, Z movlw 2 movwf cnt ; setup response waiting counter wait_resp ; wait for response for at most cnt cycles movlw 0xFF ; waiting for MMC responce call spi_io subwf resp, w ; expected responce? btfsc STATUS, Z retlw 0 ; YES - return decfsz cnt, f ; waiting period is over? goto wait_resp ; NO - keep waiting retlw 1 initMMC ; initialize SPI module and MMC bcf STATUS, RP1 bsf STATUS, RP0 ; switch to BANK 1 bsf SDI ; setup I/O ports bcf SDO bcf SCL bcf SSPSTAT ^ 0x80, SMP ; input is ready at the end of clock bcf SSPSTAT ^ 0x80, CKE ; bcf STATUS, RP0 ; switch to BANK 0 bsf SSPCON, CKP ; idle state for clock is high bsf SSPCON, SSPM1 ; set lowest speed FOSC/64 bsf SSPCON, SSPEN ; enable SPI master bsf CS ; disable MMC movlw 10 movwf cnt ; send 80 dummy clocks movlw 0xFF call spi_io decfsz cnt, f goto $-3 bcf CS ; enable MMC movlw 0x40 ; send CMD0 movwf cmd clrf arg clrf arg+1 clrf arg+2 clrf arg+3 movlw 1 ; expected response movwf resp call sendMMC addlw 0 ; set Z flag movlw 3 ; message of success btfss STATUS, Z movlw 5 ; report an error call sendString movlw 0x41 ; send CMD1 movwf cmd clrf arg clrf arg+1 clrf arg+2 clrf arg+3 clrf resp ; expected response call sendMMC addlw 0 btfss STATUS, Z goto $-10 movlw 4 ; message of success btfss STATUS, Z movlw 5 call sendString bcf SSPCON, SSPM1 ; set speed FOSC/4 return initUART ; setup the UART module bcf STATUS, RP1 bsf STATUS, RP0 ; switch to BANK 1 movlw X ; load the baud rate generator movwf SPBRG ^ 0x80 bsf TXSTA ^ 0x80, TXEN ; enable TX for 8 data bits bcf STATUS, RP0 ; switch to BANK 0 bsf RCSTA, SREN ; enable USART for 8 data bits bsf RCSTA, SPEN ; this automatically configures TX and RX pins movlw 1 ; display message1 call sendString ; if UART is working return skipBytes ; read number of bytes in cnt:cnt+1 movf skipCnt, w ; skip the bytes iorwf skipCnt+1, w btfsc STATUS, Z return ; end of skip movlw 0xFF call spi_io ; get data byte movf skipCnt, f ; decrement 16-bit counter btfsc STATUS, Z decf skipCnt+1, f decf skipCnt, f goto skipBytes skipRest514 movf skipCnt+2, w ; # of remaining bytes in sector to skip sublw LOW 514 ; skipCnt = 514 - skipCnt (16 bits) movwf skipCnt movf skipCnt+3, w btfss STATUS, C addlw 1 sublw HIGH 514 movwf skipCnt+1 call skipBytes ; skip to the end of sector return skipRest512 ; skip 512 - skipCnt:2 bytes till the movf skipCnt+2, w ; end of current sector sublw LOW 512 ; skipCnt = 512 - skipCnt (16 bits) movwf skipCnt movf skipCnt+3, w btfss STATUS, C addlw 1 sublw HIGH 512 movwf skipCnt+1 call skipBytes ; skip to the end of sector return ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% nextFile ; scans the dir list and returns the starting call getNextDirSector movlw 0x51 ; cluster of the next file movwf cmd ; arg must point to FAT1 movlw 0xFE ; expected response movwf resp call sendMMC ; send command for sector reading addlw 0 btfss STATUS, Z retlw 1 ; error movf bytes2Skip, w ; bytes2Skip = 0? iorwf bytes2Skip+1, w btfsc STATUS, Z goto read_first_byte movf bytes2Skip, w ; setup local skip bytes counter movwf skipCnt ; set up the counter of # bytes to skip movf bytes2Skip+1, w movwf skipCnt+1 skip call skipBytes ; and do the skip btfsc bytes2Skip+1, 1 ; less than 512 bytes to skip? goto sector_end ; NO - end of sector incf bytes2Skip, f ; increment the global skip number btfsc STATUS, Z incf bytes2Skip+1, f read_first_byte movlw 0xFF call spi_io ; get the first byte of the 32-byte record addlw 0 btfsc STATUS, Z ; end of the dir list? goto start_over ; YES - end of dir list movwf temp movlw 31 ; update skip number addwf bytes2Skip, f ; so that it points to the next dir record btfsc STATUS, C incf bytes2Skip+1, f movf temp, w sublw 0xE5 ; is it deleted file? btfss STATUS, Z goto not_deleted ; NOT deleted - proceed movlw 31 ; YES deleted - skip till the end of this record movwf skipCnt clrf skipCnt+1 goto skip not_deleted ; check the record starting cluster movlw 25 movwf skipCnt ; skip to the cluster word position clrf skipCnt+1 call skipBytes movlw 0xFF call spi_io ; get cluster number movwf cluster movlw 0xFF call spi_io movwf cluster+1 iorwf cluster, w btfss STATUS, Z ; cluster = 0 (fake record)? goto real_record ; NO - proceed movlw 4 movwf skipCnt ; YES - get to the next record clrf skipCnt+1 goto skip real_record movlw 0xFF ; get the file length call spi_io movwf fileLen movwf temp movlw 0xFF call spi_io movwf fileLen+1 iorwf temp, f movlw 0xFF call spi_io movwf fileLen+2 iorwf temp, f movlw 0xFF call spi_io movwf fileLen+3 iorwf temp, w btfsc STATUS, Z ; zero file length? goto skip+1 ; YES - get to the next record skip_rest movf bytes2Skip, w movwf skipCnt+2 movf bytes2Skip+1, w movwf skipCnt+3 call skipRest514 btfss bytes2Skip, 1 ; end of current dir sector? retlw 0 incf currDirSectNo, f clrf bytes2Skip clrf bytes2Skip+1 retlw 0 sector_end incf currDirSectNo, f clrf bytes2Skip clrf bytes2Skip+1 goto nextFile start_over movf bytes2Skip, w movwf skipCnt+2 movf bytes2Skip+1, w movwf skipCnt+3 call skipRest514 movlw 31 ; simulate scanning the dir list movwf currDirSectNo ; from the very beginning goto nextFile ; start over getNextDirSector movf dir, w movwf arg movf dir+1, w movwf arg+1 clrf arg+2 clrf arg+3 movlw 31 subwf currDirSectNo, w btfss STATUS, Z ; if this number is >=31, the dir list is over goto nextDirSect clrf currDirSectNo ; start from the beginning of the dir list call composeByteAddr movlw 32 ; in this case bytes2Skip = 32 movwf bytes2Skip clrf bytes2Skip+1 return nextDirSect movf currDirSectNo, w ; add curr dir sect # to arg (16-bit op) addwf arg, f btfsc STATUS, C incf arg+1, f call composeByteAddr return ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% nextCluster ; get the next file cluster # movf fat+1, w ; arg+1 = fat starting sector movwf arg+1 movf fat, w movwf arg movf cluster+1, w ; W = # sector in FAT containing the current addwf arg, f ; cluster number btfsc STATUS, C ; add this number to the starting incf arg+1, f ; FAT sector # clrf arg+2 clrf arg+3 call composeByteAddr ; sector address containing the next cluster # bcf STATUS, C ; cluster = (offset of cluster # position rlf cluster, w ; in a sector) / 2 movwf skipCnt movwf skipCnt+2 rlf cluster+1, w ; so we multiply it by 2 to get byte offset movwf skipCnt+1 movwf skipCnt+3 movlw 0x51 ; start reading sector movwf cmd movlw 0xFE movwf resp call sendMMC call skipBytes ; read next file cluster # from FAT movlw 0xFF call spi_io movwf cluster movlw 0xFF call spi_io movwf cluster+1 call skipRest512 ; skip bytes till the sector end return ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% readSector ; read sector in arg and dumps it to UART movlw 0x51 ; send CMD movwf cmd movlw 0xFE ; expected response movwf resp call sendMMC addlw 0 btfss STATUS, Z retlw 1 ; error clrf skipCnt clrf skipCnt+1 movlw 0xFF call spi_io call sendChar incf skipCnt, f btfsc STATUS, Z incf skipCnt+1, f btfss skipCnt+1, 1 goto $-7 movlw 0xFF call spi_io movlw 0xFF call spi_io retlw 0 ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% dumpSector ; read sector in arg and dumps it to UART movlw 0x51 ; send CMD movwf cmd movlw 0xFE ; expected response movwf resp call sendMMC addlw 0 btfss STATUS, Z retlw 1 ; error movlw 0xFE ; check if fileLen >= 512 andwf fileLen+1, w iorwf fileLen+2, w iorwf fileLen+3, w ; Z-bit is set iff fileLen < 512 btfss STATUS, Z goto read_whole_sect movf fileLen, w ; in this case fileLen is the number of movwf skipCnt ; bytes to read from this sector movwf skipCnt+2 movf fileLen+1, w movwf skipCnt+1 movwf skipCnt+3 bsf fileLen+3, 7 ; mark file length as negative goto data_loop ; (needed for dumpFileCluster() method) read_whole_sect clrf skipCnt ; skipCnt = 512 (16 bit) clrf skipCnt+2 movlw 2 movwf skipCnt+1 movwf skipCnt+3 movlw 2 ; 24-bit subtract 512 from fileLen subwf fileLen+1, f clrf temp clrw btfss STATUS, C incfsz temp, w subwf fileLen+2, f clrf temp clrw btfss STATUS, C incfsz temp, w subwf fileLen+3, f ; subtraction is completed data_loop movlw 0xFF call spi_io ; get data byte ; call printByte ; send it to PC call sendChar movf skipCnt, w ; decrement the loop counter btfsc STATUS, Z decf skipCnt+1, f decf skipCnt, f movf skipCnt, w iorwf skipCnt+1, w ; and check it for 0 btfss STATUS, Z goto data_loop call skipRest514 ; skip bytes till the end of sector retlw 0 ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% setBlockSize movlw 0x50 ; send CMD movwf cmd clrf arg ; arg = 512 movlw 2 movwf arg+1 clrf arg+2 clrf arg+3 clrf resp ; expected response call sendMMC addlw 0 btfss STATUS, Z retlw 1 ; error retlw 0 ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% dumpFileCluster movlw 2 ; get real cluster # subwf cluster, w ; subtract 2 (16-bit operation) movwf arg clrw btfss STATUS, C addlw 1 subwf cluster+1, w ; compose sector # movwf arg+1 clrf arg+2 clrf arg+3 movf sectPerClust, w ; multiply cluster # by the number of movwf cnt ; sectors in cluster (sectPerClust) decf cnt, f ; since this is always a power of 2 btfsc STATUS, Z ; left shifts are used instead of multiplication goto $+6 bcf STATUS, C rlf arg, f ; the resulting # might be 24-bit, if the rlf arg+1, f ; cluster number is above the 32Mb area rlf arg+2, f ; but it is never 32-bit for small MMC cards goto $-7 movf dat, w ; add to the sector offset the number addwf arg, f ; of the first sector in the data area movf dat+1, w btfsc STATUS, C incfsz dat+1, w addwf arg+1, f clrw btfsc STATUS, C addlw 1 ; here the correct C bit is not needed addwf arg+2, f call composeByteAddr ; byte address of the firsts sector in cluster movf sectPerClust, w ; LOOP OVER sectors in cluster movwf cnt+1 ; sector counter sect_loop btfsc fileLen+3, 7 ; file length negative? return call dumpSector ; No -proceed movlw 2 ; get to the next sector by adding 512 addwf arg+1, f ; to its byte address clrw clrf temp ; since the LS byte of this address is btfsc STATUS, C ; always 0, a 24-bit addition is used incfsz temp, w addwf arg+2, f clrw btfsc STATUS, C addlw 1 ; here the correct C bit is not needed addwf arg+3, f decfsz cnt+1, f ; update sector counter goto sect_loop ; and loop back if needed return ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; main bsf STATUS, RP1 ; switch to BANK 2 clrf ANSEL ^ 0x100 ; set all pins digital clrf ANSELH ^ 0x100 bcf STATUS, RP1 bsf STATUS, RP0 ; switch to BANK 1 clrf TRISA ^ 0x80 ; set all potrs for output clrf TRISB ^ 0x80 ; to prevent oscillation clrf TRISC ^ 0x80 bcf STATUS, RP0 ; switch to BANK 0 call initUART ; setup the USART module call initMMC ; setup the SSP module and initialize MMC ; STEP 1: read MBR clrf arg ; read MBR sector 0 clrf arg+1 clrf arg+2 clrf arg+3 movlw 0x51 movwf cmd movlw 0xFE ; expected response movwf resp call sendMMC ; send command for sector reading movlw LOW 0x1C2 ; read partition type movwf skipCnt movlw HIGH 0x1C2 movwf skipCnt+1 call skipBytes movlw 0xFF call spi_io movwf partType ; save partition type code movlw 3 ; skip next 3 bytes movwf skipCnt clrf skipCnt+1 call skipBytes movlw 0xFF ; read the gap between the MBR sector and the call spi_io ; first partition sector (in sectors) movwf arg movwf fat movlw 0xFF call spi_io movwf arg+1 movwf fat+1 movlw 160 ; skip 158 + 2 bytes till the end of sector movwf skipCnt clrf skipCnt+1 call skipBytes call composeByteAddr ; byte addr. of VBR of partition 1 ; STEP 2: read VBR movlw 0x51 ; read VBR sector movwf cmd movlw 0xFE ; expected response movwf resp call sendMMC ; send command for sector reading movlw 0xD ; read # of sectors per cluster # of reserved movwf skipCnt ; sectors after VBR clrf skipCnt+1 call skipBytes movlw 0xFF call spi_io movwf sectPerClust movlw 0xFF call spi_io addwf fat, f clrf temp ; save C bit btfsc STATUS, C incf temp, f movlw 0xFF call spi_io addwf temp, w addwf fat+1, f ; starting sector of FAT1 is computed movlw 6 ; skip next 6 bytes movwf skipCnt clrf skipCnt+1 call skipBytes movlw 0xFF ; read # sectors per FAT call spi_io movwf skipCnt movlw 0xFF call spi_io movwf skipCnt+1 bcf STATUS, C rlf skipCnt, f ; multiply it by 2 (for 2 copies of FAT) rlf skipCnt+1, f movf skipCnt, w addwf fat, w movwf dat movwf dir movf skipCnt+1, w btfsc STATUS, C ; computing the position of the directory list addlw 1 ; it occupies 32 secors (16Kb) addwf fat+1, w movwf dir+1 ; starting sector of dir list is computed movwf dat+1 movlw 32 addwf dat, f btfsc STATUS, C incf dat+1, f ; starting sector of the data area movlw LOW 490 movwf skipCnt movlw HIGH 490 movwf skipCnt+1 call skipBytes ; finish working with VBR ; STEP 3: loop over the directory list movlw 31 movwf currDirSectNo ; start scanning dir list from the beginning files_loop call nextFile ; get starting cluster of the next file ; in the dir list and its length ; STEP 4: loop over the file cluster chain cluster_loop call dumpFileCluster call nextCluster ; get next file cluster movlw 0xFF ; check for last file cluster xorwf cluster+1, w movwf temp movlw 0xFF xorwf cluster, w iorwf temp, w btfss STATUS, Z ; last cluster? goto cluster_loop ; NO - proceed with the next file cluster goto files_loop ; prev file is over, get the next one END