SanDisk SDSDH-1024 Product Manual - Page 88

Revision 2.2 Chapter 4 - SD Card Protocol Description SanDisk SD Card Product Manual Multiple Block Read In multiple-block read mode, the card sends a continuous flow of data blocks following the initial host read command. The data flow is terminated by a stop transmission command, CMD12. The Timing of Multiple Block Read Command timing diagram describes the timing of the data blocks, and the Timing of Stop Command (CMD12, Data Transfer Mode) timing diagram describes the response to a stop command. The data transmission stops two clock cycles after the end bit of the stop command. Timing of Multiple Block Read Command Host Command NCR Cycles Response CMD S T Content CRC E Z Z P * P S T Content CRC E Z Z P P P P P P P P P P P P P NAC Cycles Read Data DAT Z Z Z **** Z Z Z Z Z Z P ********** P S D D D ***** NAC Cycles Read Data D E P ********** P S D D D D D Timing of Stop Command (CMD12, Data Transfer Mode) Host Command NCRCycles Response CMD S T Content CRC E Z Z P *** P S T Content CRC E DAT D D D ******** D D D E Z Z ********** 4.12 Data Write Single Block Write The host selects one card for data write operation by CMD7. The host sets the valid block length for block-oriented data transfer by CMD16. The basic bus timing for a write operation is shown in the Block Write Command timing diagram. The sequence starts with a single block write command, CMD24 that determines (in the argument field) the start address. The card responds on the CMD line, and the data transfer from the host starts NWR clock cycles after the card response was received. The data is suffixed with CRC check bits to allow the card to check it for transmission errors. The card sends back the CRC check result as a CRC status token on the DAT0 line. In the case of transmission error the card sends a negative CRC status ('101'). In the case of non-erroneous transmission the card sends a positive CRC status ('010') and starts the data programming procedure. When a flash programming error occurs the card will ignore all further data blocks. In this case no CRC response will be sent to the host and, therefore, there will not be CRC start bit on the bus and the three CRC status bits will read ('111'). Block Write Command Timing Host Command CMD E Z DAT0 Z Z DAT1-3 Z Z NCR ZP* **** **** Card Response P S T Content CRC Z Z Z *** Z Z Z *** ZZ ZZ EZZP NW R Z Z P*P S Z Z P*P S Write Data Content CRC Content CRC EZ EZ PPPPPPPP CRC Status Busy Z S Status E S L*L E Z Z XXXXXXXXXZ © 2004 SanDisk Corporation 4-44 12/08/04