Hello, this is Taka, I have tried to use "SDFileSystem_HelloWorld" or "SDHCFileSystem" but it doesn't work. I know how to work SD-Card and checking the signal by oscilloscope. I use two type of SD-card, and the sequence are like these. 1) Use 2GB SD-card - It can be reset. CMD0 works and SD-card returns R1-response as 0x01, mean "In Idle State". -Then, the program tried to do CMD41 as initialize, but the "In Idle State" bit couldn't be cleared. -The error code via terminal shows this error Timeout waiting for v2.x card init card = 0 Didn't get a response from the disk Set 512-byte block timed out 2)Use 8GB SDHC-card -CMD0 doesn't work. SDO of the card doesn't work at all. -The error is this No disk, or could not put SD card in to SPI idle state init card = 0 Didn't response from the disk Set 512-byte block time out I checked the circuit many times but it seems OK.