Привет всем! Ребята, кто-нибудь работал с MMC-карточкой не в SPI-режиме, а в ее родном !? Не получается ее ресетнуть и инициализировать!!! Делаю все по спецификации, а ничего не выходит !
Ответы не приходят. Может, есть какие-то подводные камни, мне не известные!? Вот последовательность действий:
Power-up
1- Apply power to the bus, communication voltage range (2.7-3.6V)
2- Set clock to 400KHz, or less
3- Wait for 1ms, then wait for 74 more clock cycles
4- Send CMD0 to reset the bus, keep CS line high during this step.
5- Send CMD1, with the intended voltage range in the argument (either 0x00FF8000 or 0x00000080)
6- Receive R3
7- If the OCR busy bit is ‘0’, repeat steps 5 and 6
8- From the R3 response argument the host can learn if the card is a High Voltage or Dual Voltage card.
If the argument is 0x80FF8000 the card is only High Voltage, if the argument is 0x80FF8080 the card is
Dual Voltage.
9- If R3 returned some other value, the card is not compliant (since it should have put itself into inactive
state, due to voltage incompatibility, and not respond); in such a case the host must power down the bus
and start its error recovery procedure (the definition of error recovery procedures is host dependent and
out of the scope of this application note)
Заранее благодарю за помощь !
MMC, MMC карточка в MMC режиме (1,4,8-ми битный)
Feb 27 2011, 15:12
