NXP Semiconductors LPC43 Series User Manual

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NXP Semiconductors LPC43 Series User Manual Manual pdf 455 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 455 of 1269NXP Semiconductors UM10503Chapter 20: LPC43xx SD/MMC interface• Program the block size (BLKSIZ) register as shown below.• Program the Byte Count (BYTCNT) register as shown below.20.7.5.2.4 Sending Command Completion Signal DisableWhile waiting for the Command Completion Signal (CCS) for an outstanding RW_BLK,the cpu can send a Command Completion Signal Disable (CCSD).• Send CCSD - Module sends CCSD to the CE-ATA device if the send_ccsd bit is set inthe CTRL register; this bit is set only after a response is received for the RW_BLK.• Send internal Stop command - Send internally generated STOP (CMD12) commandafter sending the CCSD pattern. If send_auto_stop_ccsd bit is also set when thecontroller is programmed to send the CCSD pattern, the Module sends the internallygenerated STOP command on the CMD line. After sending the STOP command, theModule sets the Auto Command Done bit in the RINTSTS register.20.7.5.2.5 Recovery after Command Completion Signal Time-outIf time-out happened while waiting for Command Completion Signal (CCS), the cpu needsto send Command Completion Signal Disable (CCSD) followed by a STOP command toabort the pending ATA command. The cpu can program the Module to send internallygenerated STOP command after sending the CCSD pattern• Send CCSD - Set the send_ccsd bit in the CTRL register.• Reset bit 13 of the Command register (wait_prvdata_complete) to 0 in order to makethe Module send the command at once, even though there is a data transfer inprogress.• Send internal STOP command - Set send_auto_stop_ccsd bit in the CTRL register,which programs the cpu controller to send the internally generated STOP command.After sending the STOP command, the Module sets the Auto Command Done bit inthe RINTSTS register.20.7.5.2.6 Reduced ATA Command SetIt is necessary for the CE-ATA device to support the reduced ATA command subset. Thefollowing details discuss this reduced command set.Table 342. BLKSIZ registerBits Value Comment31:16 0 Reserved bits as zeroes (0)15:0 512, 1024, 4096 MMC block size can be 512, 1024, or 4096bytes as negotiated by CPUTable 343. BYTCNT registerBits Value Comment31:0 N  block_size byte_count should be integral multiple ofblock size; for ATA media access commands,byte count should be multiple of 4KB. (N block_size = X  4KB, where N and X areintegers)