MultiMediaCard
TM
23
Sep.22.2005
Revision 0.3
5.5 MultiMediaCard Registers
Within the card interface six registers are defined: OCR, CID, CSD, EXT_CSD, RCA and DSR. These can be accessed
only by corresponding commands (see Chapter 6.6). The OCR, CID and CSD registers carry the card/content specific
information, while the RCA and DSR registers are configuration registers storing actual configuration parameters. The
EXT_CSD register carries both, card specific information and actual configuration parameters.
5.5.1 OCR Register
The 32-bit operation conditions register stores the V
DD
voltage profile of the card. In addition, this register includes a sta-
tus information bit. This status bit is set if the card power up procedure has been finished. The OCR register shall be
implemented by all cards.
The supported voltage range is coded as shown in Table , for High Voltage and Dual voltage MultiMediaCards. As long as
the card is busy, the corresponding bit (31) is set to LOW, the ‘wired-and’ operation, described in Chapter 6.1.2 yields
LOW, if at least one card is still busy.
5.5.2 CID Register
The Card IDentification (CID) register is 128 bits wide. It contains the card identification information used during the card
identification phase (MultiMediaCard protocol). Every individual flash or I/O card shall have an unique identification num-
ber. Every type of MultiMediaCard ROM cards (defined by content) shall have an unique identification number.
The structure of the CID register is defined in the following paragraphs:
OCR bit
VDD voltage window
High Voltage
MultimediaCard
000 0000b
0b
000 0000b
1 1111 1111b
000 0000b
Dual voltage
MultiMediaCard
00 00000b
1b
000 0000b
1 1111 1111b
000 0000b
[6:0]
[7]
[14:8]
[23:15]
[30:24]
[31]
Reserved
1.65 - 1.95
2.0-2.6
2.7-3.6
Reserved
card power up status bit (busy)
a
a.This bit is set to LOW if the card has not finished the power up routine
Name
Field
MID
OID
PNM
PRV
PSN
MDT
CRC
-
Width
8
16
48
8
32
8
7
1
CID-slice
[127:120]
[119:104]
[103:56]
[55:48]
[47:16]
[15:8]
[7:1]
[0:0]
CID Value
0x15
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Manufacturer ID
OEM/Application ID
Product name
Product revision
Product serial number
Manufacturing date
CRC7 checksum
not used, always ’1’
Table 5-12 : The CID fields