I'm trying to access a Samsung K9K4G08U0M NAND flash device with an Altera Cyclone II.
The NAND flash requires some setup signals do to a read from flash, ie. CLE, nCE, nWE, ALE, nRE, and IO. After I have setup these signals, the device's R/nB signal goes low, as expected, but it never goes high again!!! It just stays in the Busy state indefinitely!
The R/nB signal should stay low for a maximum of 25us for a read according to the data sheet.
Even when I execute the Reset command to the flash, the flash hangs in the Busy state.
I have already checked the hardware for shorts, the power rails for noise, and I have even replaced the NAND flash chip. I have checked the timing requirements for the setup signals and I have tried slowing everything down to half speed.
I think my setup signals are correct, because the flash responds to them, but I may be wrong.
Does anyone have any experience with this problem or advice for me? It would be greatly appreciated. Thanx Eric