Our company is a member of MMCA and we develop MMC card side controllers. Our 16MB, 32MB and 64MB cards work well with the Nokia 9210. However, we found a problem when using our 128MB cards on the 9210.
Specifically, during power on initialization the 9210 has a timeout period of about 260ms for a card to finish its initialization process. It sends at most six cycles of CMD1 to ask whether a card is ready or not. Our low density cards (64MB and below) can finish the power on initialization in less than 260ms. However, the 128MB cards require more time to become ready, and thus failed by the 9210. It seems that the new Nokia 3650 also has the same problem.
According to MMC system specifications, a host should continue sending CMD1 when a card is still not ready for up to 1 second during power on initialization. The timeout periods on a Nokia 9210 and a Nokia 3650 are far less than 1 second. This might create compatibility issues with high density cards. The power on initialization time of a card is actually vender dependent. The 260ms (six CMD1 cycles) timeout period may be long enough for 128MB cards from some venders. However, according to MMC system specifications, the initialization timeout should be 1 second.
Is it possible to modify the firmware of the 9210 and 3650 (and latter mobile models) so that the power on timeout is changed to 1 second? Your attention and supports are highly appreciated.