![NXP Semiconductors LPC43Sxx Скачать руководство пользователя страница 579](http://html1.mh-extra.com/html/nxp-semiconductors/lpc43sxx/lpc43sxx_user-manual_1721827579.webp)
UM10503
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
579 of 1441
NXP Semiconductors
UM10503
Chapter 22: LPC43xx/LPC43Sxx SD/MMC interface
If the DF flag is 0, then in case of a read, the Module waits for data. After the data
time-out period, it gives a data time-out error.
22.7.5.1 Read_Wait Sequence
Read_wait is used with only the SDIO card and can temporarily stall the data
transfer-either from function or memory-and allow the cpu to send commands to any
function within the SDIO device. The cpu can stall this transfer for as long as required.
The Module provides the facility to signal this stall transfer to the card. The steps for doing
this are:
1. Check if the card supports the read_wait facility; read SRW (bit 2) of the CCCR
register @0x08. If this bit is 1, then all functions in the card support the read_wait
facility. Use CMD52 to read this bit.
2. If the card supports the read_wait signal, then assert it by setting the read_wait (bit 6)
in the CTRL register @0x00.
3. Clear the read_wait bit in the CTRL register.
22.7.5.2 CE-ATA Data Transfer Commands
This section describes the CE-ATA data transfer commands. For information on the basic
settings and interrupts generated for different conditions, refer to "Data Transfer
Commands".
22.7.5.2.1
Reset and Device Recovery
Before starting CE-ATA operations, the cpu should perform an MMC reset and
initialization procedure. The cpu and device should negotiate the MMC TRAN state
(defined by the MultiMedia Card System Specification) before the device enters the MMC
TRAN state. The cpu should follow the existing MMC Card enumeration procedure in
order to negotiate the MMC
TRAN state. After completing normal MMC reset and initialization procedures, the cpu
should query the initial ATA Task File values using RW_REG/CMD39.
By default, the MMC block size is 512 bytes-indicated by bits 1:0 of the srcControl register
inside the CE-ATA device. The cpu can negotiate the use of a 1KB or 4KB MMC block
size. The device indicates MMC block sizes that it can support through the srcCapabilities
register; the cpu reads this register in order to negotiate the MMC block size. Negotiation
is complete when the cpu controller writes the MMC block size into the srcControl register
bits 1:0 of the device.
Table 396. Parameters for CMDARG register
Bits
Contents
Value
31
R/W flag
1
30-28
Function number
0, for CCCR access
27
RAW flag
1, read after write
26
Don’t care
-
25-9
Register address
0x0D
8
Don’t care
-
7-0
Write data
Function number to be aborted