Table 138. Command Token Format
Bit Position
Width (Bits)
Value
47
1
46
1
45:40
39:8
32
-
7:1
7
0
6
-
1
‘0’
‘1’
-
‘1’
Transmission
bit
Command
Index
Start bit
Argument
CRC7
End bit
Description
Response Token Format
There are five types of response tokens (R1 to R5). As shown in Figure 88, 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 88. Response Token Format
R1, R4, R5
0
0
0
0
0
0
Content
CRC
1
1
Total Length = 48 bits
R3
R2
Content
Total Length = 48 bits
Content = CID or CSD
Total Length = 136 bits
CRC
1
Table 139. R1 Response Format (Normal Response)
Bit Position
Width (bits)
Value
47
1
46
1
45:40
39:8
32
-
7:1
7
0
6
-
1
‘0’
‘0’
-
‘1’
Transmission
bit
Command
Index
Start bit
Card Status
CRC7
End bit
Description
Table 140. R2 Response Format (CID and CSD registers)
Bit Position
Width (bits)
Value
135
1
134
1
[133:128]
6
[127:1]
0
32
-
1
‘0’
‘0’
‘111111’
‘1’
Transmission
bit
Start bit
Reserved
Argument
End bit
Description
138
AT8xC51SND2C
4341D–MP3–04/05
ATMEL [ ATMEL ]
