NXP Semiconductors freescale K51 Series Reference Manual

Boot operation will be terminated when all contents of the enabled boot data are sent tothe master. After boot operation is executed, the slave shall be ready for CMD1 operationand the master needs to start a normal MMC initialization sequence by sending CMD1.DAT[0]CMDCLK50msmax1 sec.max010 SSS EEECMD1 RESP CMD2 RESP CMD3 RESP512bytes+CRC512bytes+CRCBoot terminintedMin 8 clocks + 48 clocks = 56 clocks required fromCMD singal high to next MMC commandFigure 49-37. Multimediacard state diagram (normal boot mode)49.5.9.2 Alternative boot operationThis boot function is optional for the device. If bit 0 in the extended CSD byte[228] is setto '1', the device supports the alternative boot operation.After power-up, if the host issues CMD0 with the argument of 0xFFFFFFFA after 74clock cycles, before CMD1is issued or the CMD line goes low, the slave recognizes thatboot mode is being initiated and starts preparing boot data internally.Within 1 second after CMD0 with the argument of 0xFFFFFFFA is issued, the slavestarts to send the first boot data to the master on the DAT line(s).If boot acknowledge is enabled, the slave has to send the acknowledge pattern '010' to themaster within 50ms after the CMD0 with the argument of 0xFFFFFFFA is received. Ifboot acknowledge is disabled, theslave will not send out acknowledge pattern '010'.The master can terminate boot mode by issuing CMD0 (Reset).Boot operation will be terminated when all contents of the enabled boot data are sent tothe master. After boot operation is executed, the slave shall be ready for CMD1 operationand the master needs to start a normal MMC initialization sequence by sending CMD1.Functional descriptionK51 Sub-Family Reference Manual, Rev. 6, Nov 20111376 Freescale Semiconductor, Inc.