K60P100M100SF2RM Datasheet, PDF (1663/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Chapter 52 Secured digital host controller (SDHC)
is set to 1, DTDSEL is set to 1, MSBSEL is set to 1. Note DMAEN should be
configured as 0 in polling mode. And if BCEN is configured as 1 in polling mode,
better to configure blk no in Bock Attributes Register to the max value.
7. When the step 6 is configured, boot process will begin. Software need to poll the data
buffer ready status to read the data from buffer in time. If boot time out (ack data
time out in 50ms or data time out in 1s), host will send out the interrupt and software
need to send CMD0 with reset and then configure boot enable bit to 0 to stop this
process. After command completed, configure MMCBOOT[BOOTEN] to 0 to
disable boot. After at least 8 clocks from command completed, card is ready for
identification step.
8. If no time out, software need to decide when to stop the boot process, and send out
the CMD0 with reset and then after command completed, configure
MMCBOOT[BOOTEN] to stop the process. After 8 clocks from command
completed, slave(card) is ready for identification step.
9. Reset the host and then can begin the normal process.
52.6.6.3 Fast boot application case (in DMA mode)
In the boot application case, because the image destination and the image size are
contained in the
beginning of the image, need to switch DMA parameters on the fly during MMC fast
boot.
In fast boot, host can use ADMA2(advanced DMA2) with two destinations.
The detail flow:
1. Software need to configure init_active bit (system control register bit 27) to make
sure 74 card clocks are finished.
2. Software need to configure MMCBOOT[BOOTEN] to 1; and
MMCBOOT[BOOTMODE] to 0 (normal fast boot), to 1(alternative boot); and
MMCBOOT[BOOTACK] to select the ack mode or not. In DMA mode, configure
MMCBOOT[AUTOSABGEN] to 1 for enable automatically stop at block gap
feature. Also configure MMCBOOT[BOOTBLKCNT] to set the VAULE1(value of
block count that need to trans first time), that host will stop at block gap when card
block counter is equal to this value. And need to configure
MMCBOOT[DTOCVACK] to select the ack timeout value according to the sd clk
frequence.
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.
1663