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sdc: make some space in memory for buffer CRC
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@ -65,12 +65,19 @@
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.equ SDC_BUFDIRTY1 SDC_BUFSEC1+2
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; The contents of the buffer.
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.equ SDC_BUF1 SDC_BUFDIRTY1+1
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; CRC bytes for the buffer. They're placed after the contents because that makes
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; things easier processing-wise. Because the SD card sends them right after the
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; contents, all we need to do is read SDC_BLKSIZE+2.
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; IMPORTANT NOTE: This is big endian. The SD card sends the MSB first, so we
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; keep it in memory this way.
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.equ SDC_CRC1 SDC_BUF1+SDC_BLKSIZE
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; second buffer has the same structure as the first.
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.equ SDC_BUFSEC2 SDC_BUF1+SDC_BLKSIZE
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.equ SDC_BUFSEC2 SDC_CRC1+2
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.equ SDC_BUFDIRTY2 SDC_BUFSEC2+2
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.equ SDC_BUF2 SDC_BUFDIRTY2+1
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.equ SDC_RAMEND SDC_BUF2+SDC_BLKSIZE
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.equ SDC_CRC2 SDC_BUF2+SDC_BLKSIZE
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.equ SDC_RAMEND SDC_CRC2+2
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; *** Code ***
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; Wake the SD card up. After power up, a SD card has to receive at least 74
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@ -350,8 +357,8 @@ sdcReadBlk:
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jr .error ; timeout. error out
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.loop1end:
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; We received our data token!
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; Data packets follow immediately, we have 512 of them to read
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ld bc, SDC_BLKSIZE
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; Data packets follow immediately, we have 512+CRC of them to read
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ld bc, SDC_BLKSIZE+2
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ld hl, (SDC_BUFPTR) ; HL --> active buffer's sector
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; It sounds a bit wrong to set bufsec and dirty flag before we get our
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; actual data, but at this point, we don't have any error conditions
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@ -372,9 +379,6 @@ sdcReadBlk:
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cpi ; a trick to inc HL and dec BC at the same time.
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; P/V indicates whether BC reached 0
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jp pe, .loop2 ; BC is not zero, loop
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; Read our 2 CRC bytes
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call sdcIdle
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call sdcIdle
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; success! wait until card is ready
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call sdcWaitReady
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xor a ; success
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@ -430,7 +434,10 @@ sdcWriteBlk:
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call sdcSendRecv
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; Sending our data token!
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ld bc, SDC_BLKSIZE
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ld bc, SDC_BLKSIZE+2 ; +2 for CRC. (as of now, however, that
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; CRC isn't properly updated. Because
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; CMD59 isn't enabled, it doesn't
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; matter)
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ld hl, (SDC_BUFPTR)
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inc hl ; sector MSB
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inc hl ; dirty flag
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@ -442,9 +449,6 @@ sdcWriteBlk:
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cpi ; a trick to inc HL and dec BC at the same time.
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; P/V indicates whether BC reached 0
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jp pe, .loop ; BC is not zero, loop
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; Send our 2 CRC bytes. They can be anything
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call sdcIdle
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call sdcIdle
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; Let's see what response we have
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call sdcWaitResp
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and 0b00011111 ; We ignore the first 3 bits of the response.
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@ -464,7 +468,6 @@ sdcWriteBlk:
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; Before returning, wait until card is ready
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call sdcWaitReady
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xor a
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; A is already 0
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jr .end
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.error:
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; try to preserve error code
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