SD Card, CMD38 - strange erase problem
Posted on 2009-03-29
Developing my current microcontroller project I discovered a strange behavior trying to erase some SDHC card labeled PQI but reported from CID as 'Transcent SM 00000, rev. 1.0'. I searched this manufacturer and seems to be pirate
Anyhow, after CMD32 and 33 (both acknowledged ok by R1=0x00) and after CMD38 -> erase execute (this one too acknowledged ok, R1=0x00) my card isn't erased ! I tried many START-END sector combinations. Instead I get for all SCR (card status register or R2) = 0x0002 meaning 'Write-protect erase-skip/lock/unlock command failed'.
Ok but card is new, lock is in unlock state (checked) and I can read/write single/multiple sectors without any problems.
I tried to get so called 'Write Protected' sectors (to see if have ones) by CMD30 and report is 'Illegal command' so card don't have that feature.
One more thing... after CMD38... this card replies immediatelly by 0xFF after 2 bytes 0x00 so I observed too short 'time of erase' or erase isn't executed at all. For all other cards this takes a little while erasing to complete... (keeping 0x00 bus as busy)
So is possible 'Erase' not to be implemented as long as card manufacturer is questionable ?...
Any ideas ? Tnx in advance,