3 stream data write, 4 stream data read – Intel PXA26X User Manual
Page 526
15-14
Intel® PXA26x Processor Family Developer’s Manual
MultiMediaCard Controller
In a block data read, the following parameters must be specified:
•
The data transfer is a read.
•
The block length, if the block length is different from the previous block data transfer or this is
the first time that the parameter is being specified.
•
The number of blocks to be transferred.
•
The receive data time-out period.
The controller will mark the data transaction as timed out if data is not received before the time-out
period. The delay for the time-out period is defined as:
The software is required to calculate this value and write the appropriate value into the
MMC_RDTO register.
15.3.2.3
Stream Data Write
The stream data write looks like the single block write except a stop transmission command is sent
in parallel with the last six bytes of data.
After turning the clock on to start the command sequence, the software must start the process of
filling the MMC_TXFIFO and starting the clock as describe in
. The software must then wait for the MMC_I_REG[STOP_CMD] interrupt. This interrupt
indicates that the MMC controller is ready for the stop transmission command. The software must
then stop the clock, write the registers for a stop transmission command, and then start the clock.
At this point, the software must wait for the MMC_I_REG[DATA_TRAN_DONE] and
MMC_I_REG[PRG_DONE] interrupts.
In a stream data write, the following parameters must be specified:
•
The data transfer is a write.
•
The data transfer is in stream mode
•
The block length, if the block length is different from the previous block data transfer or this is
the first time that the parameter is being specified.
•
The number of blocks to be transferred as 0xffff.
15.3.2.4
Stream Data READ
The stream data read looks like the single block read except a stop transmission command must be
sent after the data transfer.
After turning the clock on to start the command sequence, the software must start the process of
reading the MMC_RXFIFO as described in
Section 15.3.2.2, “Block Data Read”
When it uses the DMA, the software must also configure the DMA to send an interrupt after all
data has been read. After the DMA interrupt or the program has read all of the data, the software
must send the stop transmission command. The MCC_STAT[DATA_TRAN_DONE] bit is not set
until after software sends the stop transmission command.
In a stream data read, the following parameters must be specified:
Time-out Delay
MMC_RDTO[READ_TO]
(
)
128
(
)
×
10
7
------------------------------------------------------------------------------------------ sec
=