Hello, we want to exchange an SD-card in an existing design by an eMMC because we expect a higher robustness compared to the SD-Card in a socket. The read/write bandwidth might also be higher (8 bit interface instead of 4 bit), but of cource this also depends on the type of flash, (MLC, SLC, ...) and the integrated controller. I read that the middleware supports eMMC. We have not used eMMC in the past and therefor have no real experience this this type of flash memory so I askey our distributor for advice which one we could use. Answer was that eMMC cannot be used with the Microcontroller because modern eMMC have a JEDEC interface, the CPU does not have it ?!? I was confused, be he is the specialist... Now my question: Can anyone give me a partnumber of an eMMC that is supported by the Keil Middleware and that I can connect to LPC 4357 or STM32F7xx ? Somewhere I read which version of eMMC standard is supported by the middleware (V4.2?) but I cannot find this right now. I found eMMC components V5.0 and V5.1, but I'm not sure about compatiblity with earlier specification versions. Thank you.
Hello Gunnar,
basically you can use any eMMC device you can get as they use the same or similar interface as SD cards (4 or 8-bit data lines, command and clock line).
Keil Middleware supports eMMC specification 4.41, but you should not have any problem using any device which is 5.0 compatible, because they are backward compatible. It is just that memory card controllers available in microcontrollers today don't support any specification above 4.41 and you won't be able to achieve data transfer performances rated by your device. But when comparing with SD card you currently use, the performance should increase.
Take a look at devices and modules on www.hardkernel.com/.../prdt_info.php if you want to play a bit with eMMC devices. They can be fitted into SD card socket. Some modules use SD1N9DW4-16G device, which also works with FileSystem. You can also take a look at MTFC2GMVEA device for example.
Thank you. I will add a socket to my testboard to make test with different eMMC and compare the performance with (µ)SD (8bit vs. 4bit).