NXP Semiconductors LPC43 Series User Manual

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NXP Semiconductors LPC43 Series User Manual Manual pdf 456 page image

UM10503 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.User manual Rev. 1.3 — 6 July 2012 456 of 1269NXP Semiconductors UM10503Chapter 20: LPC43xx SD/MMC interface• IDENTIFY DEVICE - Returns 512-byte data structure to the cpu that describesdevice-specific information and capabilities. The cpu issues the IDENTIFY DEVICEcommand only if the MMC block size is set to 512 bytes; any other MMC block sizehas indeterminate results.The cpu issues RW_REG for the ATA command, and the data is retrieved throughRW_BLK.The cpu controller uses the following settings while sending RW_REG for the IDENTIFYDEVICE ATA command. The following lists the primary bit• CMD register setting - data_expected field set to 0• CMDARG register settings:– Bit [31] set to 0– Bits [7:2] set to 128.• Task file settings:– Command field of the ATA task file set to ECh– Reserved fields of the task file cleared to 0• BLKSIZ register bits [15:0] and BYTCNT register - Set to 16The cpu controller uses the following settings for data retrieval (RW_BLK):\• CMD register settings:– ccs_expect set to 1– data_expected set to 1• CMDARG register settings:– Bit [31] set to 0 (Read operation)Data Count set to 1 (16'h0001)• BLKSIZ register bits [15:0] and BYTCNT register - Set to 512 IDENTIFY DEVICE canbe aborted as a result of the CPU issued CMD12.– READ DMA EXT - Reads a number of logical blocks of data from the device usingthe Data-In data transfer protocol. The cpu uses RW_REG to issue the ATAcommand and RW_BLK for the data transfer.– WRITE DMA EXT - Writes a number of logical blocks of data to the device usingthe Data-Out data transfer protocol. The cpu uses RW_REG to issue the ATAcommand and RW_BLK for the data transfer.– STANDBY IMMEDIATE - No data transfer (RW_BLK) is expected for this ATAcommand, which causes the device to immediately enter the most aggressivepower management mode that still retains internal device context.• CMD Register setting - data_expected field set to 0CMDARG register settings:– Bit [31] set to 1– Bits [7:2] set to 4• Task file settings: