GD32F20x User Manual
639
24.5.3.
Responses
All responses are sent on the CMD line. The response transmission always starts with the left
bit of the bit string corresponding to the response code word. The code length depends on
the response type.
Responses types
There are 7 types of responses show as follows.
R1 / R1b :
normal response command.
R2 :
CID, CSD register.
R3 :
OCR register.
R4 :
Fast I/O.
R5 :
Interrupt request.
R6 :
Published RCA response.
R7 :
Card interface condition.
The SD Memory Card support five types of them, R1 / R1b, R2, R3, R6, R7. And the SD I/O
Card and MMC supports additional response types named R4 and R5, but they are not exactly
the same for SD I/O Card and MMC.
Responses format
Responses have two formats, as show in
Figure 24-8. Response Token Format
all
responses are sent on the CMD line. The code length depends on the response type. Except
R2 is 136 bits length, others are all 48 bits length.
Figure 24-8. Response Token Format
0
1
Content
CRC
1
Total length = 48 bits
0
1
Content = CID or CSD
CRC
1
Total length = 136 bits
A response always starts with a start bit (always 0), followed by the bit indicating the direction
of transmission (card = 0). A value ‘x’ in the tables below indicates a variable entry. All
responses except for the type R3 are protected by a CRC. Every command code word is
terminated by the end bit (always 1).
Summary of Contents for GD32F20 Series
Page 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Page 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Page 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Page 385: ...GD32F20x User Manual 385 ...
Page 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...