MC2GH256NMCA-2SA00 SAMSUNG [Samsung semiconductor], MC2GH256NMCA-2SA00 Datasheet - Page 45

• Manufacturer Part Number: MC2GH256NMCA-2SA00
• Description: SAMSUNG MultiMediaCard
• Manufacturer: SAMSUNG [Samsung semiconductor]

6.2.4 Bus Testing Procedure
By issuing commands CMD19 and CMD14 the host can detect the functional pins on the bus. In a first step, the host
sends CMD19 to the card, followed by a specific data pattern on each selected data lines. The data pattern to be sent per
data line is defined in the table below. As a second step, the host sends CMD14 to request the card to send back the
reversed data pattern. With the data pattern sent by the host and with the reversed pattern sent back by the card, the func-
tional pins on the bus can be detected.
The card ignores all but the two first bits of the data pattern. Therefore, the card buffer size is not limiting the maximum
length of the data pattern. The minimum length of the data pattern is two bytes, of which the first two bits of each data line
are sent back, by the card, reversed. The data pattern sent by the host may optionally include a CRC16 checksum, which
is ignored by the card.
The card detects the start bit on DAT0 and synchronizes accordingly the reading of all its data inputs.
The host ignores all but the two first bits of the reverse data pattern. The length of the reverse data pattern is eight bytes
and is always sent using all the card’s DAT lines (See Table through Table ). The reverse data pattern sent by the card
may optionally include a CRC16 checksum, which is ignored by the host.
The card has pull ups in all data inputs. In cases where the card is connected to only 1bit or only 4bit HS-MMC system, the
input value of the upper bits (e.g. DAT1-DAT7 or DAT4-DAT7) are detected as logical “1” by the card. .
Revision 0.3
DAT0
DAT1
DAT2
DAT3
DAT4
DAT5
DAT6
DAT7
Data
line
0,10xxxxxxxxxx,[CRC16],1
Data pattern sent by the host
Start Bit
0
Table 6-3 : 1-bit Bus Testing Pattern
0,01000000,[CRC16],1
0,00000000,[CRC16],1
0,00000000,[CRC16],1
0,00000000,[CRC16],1
0,00000000,[CRC16],1
0,00000000,[CRC16],1
0,00000000,[CRC16],1
0,00000000,[CRC16],1
Reversed pattern sent by the card
Data Pattern
1 0 x x x x ... x x
45
End bit
1
Start bit defines beginning of pattern
No data pattern sent
No data pattern sent
No data pattern sent
No data pattern sent
No data pattern sent
No data pattern sent
No data pattern sent
MultiMediaCard
Notes
Sep.22.2005
TM