Hi, I'm trying to communicate with a SD card on MCI bus. I've implemented the structure of software released by NXP site (LPC23xx_24xxSampleSoftware.r5) to build my commands. When I send a comand to the card I've controlled the signals with my oscilloscope and I find them correct but the card doesn't answer. Have you got any suggestion to me? Have you got any simple piece of software that configure the card and send a command correctly? The amazing aspect for me is that the electrical signals are correct, so I don't know what to do to solve this problem...
Thanks and bye
Demis
Are the timing of the signals also correct, so you don't run them too fast?
Sure! I've configured the peripherals at 320 kHz (< 400 kHz as stated in SD card specifications for identification card mode) and I've controlled each bit with the oscilloscope. All seems right but the card doesn't answer!!! Specifically, first I send CMD0 (GO_IDLE_STATE) for which no response is required (therefore from a theorical point of view I don't know if it is received and interpreted correctly by the card...). Then I send CMD55 before sending ACMD41 but the card dosen't answer to CMD55 command (as required by specification) and I don't know why because there is no way to know the status of the card if it doesn't send any response! The fun aspect of the problem is that when I began to test my software the card answered correctly to the whole identification sequence for some times! Then it stopped answering till now and I don't know why...