T

T

S

2

G

S

D

1

5

0

0

2GB 150x Secure Digital Card

Transcend Information Inc.

5

The CRC protection algorithm for block data is a 16 bit CCITT polynomial.

Figure 8: Response token format

In the CMD line the MSB bit is transmitted first the LSB bit is the last.

When the wide bus option is used, the data is transferred 4 bits at a time (refer to Figure 10). Start and end bits, as

well as the CRC bits, are transmitted for every one of the DAT lines. CRC bits are calculated and checked for every

DAT line individually. The CRC status response and Busy indica-tion will be sent by the card to the host on DAT0 only

(DAT1-DAT3 during that period are don’t care).