Rainbow Electronics AT89C51SND1C - Manual (Page 112)

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AT8xC51SND1C
4109E–8051–06/03
Table 105. Command Token Format
Response Token Format There are five types of response tokens (R1 to R5). As shown in Figure 76, responses
have a code length of 48 bits or 136 bits. A response token is preceded by a Start bit: a
low level on MCMD line and succeeded by an End bit: a high level on MCMD line. The
command content is preceded by a Transmission bit: a low level on MCMD line for a
response token (card to host) and succeeded (R1,R2,R4,R5) or not (R3) by a 7 - bit
CRC.
Response content contains mirrored command and status information (R1 response),
CID register or CSD register (R2 response), OCR register (R3 response), or RCA regis-
ter (R4 and R5 response).
Figure 76. Response Token Format
Table 106. R1 Response Format (Normal Response)
Table 107. R2 Response Format (CID and CSD registers)
Bit Position 47 46 45:40 39:8 7:1 0
Width (Bits) 1 1 6 32 7 1
Value ‘0’ ‘1’ - - - ‘1’
Description
Start bit
Transmission
bit
Command
Index
Argument CRC7 End bit
Bit Position 47 46 45:40 39:8 7:1 0
Width (bits) 1 1 6 32 7 1
Value ‘0’ ‘0’ - - - ‘1’
Description
Start bit
Transmission
bit
Command
Index
Card Status CRC7 End bit
Bit Position 135 134 [133:128] [127:1] 0
Width (bits) 1 1 6 32 1
Value ‘0’ ‘0’ ‘111111’ - ‘1’
Description
Start bit
Transmission
bit
Reserved Argument End bit
0
Total Length = 48 bits
Content CRC 0 1 R1, R4, R5
0
Total Length = 136 bits
Content = CID or CSD CRC 0 1 R2
0
Total Length = 48 bits
Content 0 1 R3