Hello Everyone, I have developed an application based on SD card using LPC2468. I have initialized SD card with MCI Bus . I have tested it for Sandisk 4GB/8GB speed class 2 SD card for which it is working fine. Now I want to use Sandisk 4GB SD card with Speed class 4 . I have tested this new sd card with my existing code it is getting initialized but while reading block of 512 it is getting transmit underrun error. Then i checked in the LPC2468 datasheet mentioning that its MCI supports SD Card Physical Layer Specification, v0.96. So i have following doubts: 1. Does this mean that my host controller is not compatible to run speed class 4 or Higher speed class SD cards? 2.If it is then how should i set MCI clock frequency so that it can access the sd card with 4MB/s speed(speed class 4). In the application MCLK is set to CCLK which is 60MHZ. During initialization process MCI block is getting 400KHZ and for data access it is set to 15MHZ i.e MCLK/(2*(clkdiv+1)) = 60MHZ/(2*(1+1))
Need your suggestions and help.
Regards, Sudha A.