Hi,
I am currently looking at using the RCM3900 and a MicroSD card in a project, however, the rabbit libraries only appear to support the initial SD version 1.0 specification (<=1GB) .
As these cards are slowly geting harder to get hold of and as it would be nice to use even more flash memory, I am looking at modifying the rabbit SDFLASH.LIB to accomodate the SD V2 specification. As far as I can tell from the specification, there are no physical differences, however, the newer standard has a number of changes to the internal registers that need to be accounted for.
Has any one else come across these changes and/or managed to find a way around them? I am slightly concerned that it may not be possible or there will be a lot more work than anticipated.
Simplified SD Standard:-
https://www.sdcard.org/downloads/pls/simplified_specs/Part_1_Physical_Layer_Simplified_Specification_Ver_3.01_Final_100518.pdf
Any tips or ideas would be greatly appreciated.
Regards,
Stuart
Good morning,
The following microSD™ Cards were evaluated by Rabbit Semiconductor for use with RCM3900, RCM4300
RabbitCore modules and future Rabbit-based devices that support microSD™ Cards, and were found to
interface correctly with these devices. While other microSD™ Cards may work correctly with a PC, some
cards have exhibited lockup behavior under certain conditions when running in the SPI mode, which is used
by the RCM3900 and RCM4300.
Kinnston 256MB, 512MB, 1GB
SanDisk 256MB, 512MB, 1GB
Toshiba 1GB
Transcend 1GB
Any original SD standard capacity card (i.e. not SDHC, not SDXC, nor other future SD card revisions) that meets the following requirements is expected to work with Dynamic C’s standard SDFLASH.LIB and SD_FAT.LIB functionality:
• maximum 2 GB size
• FAT16 format (FAT32 or exFAT formatted SD cards must be reformatted as FAT16)
• full support of SD’s legacy SPI communication mode
• standard 19-byte CSD format (latest functionality supports both CRC16 and CRC7 calculation check modes)
It is our customer’s responsibility to source their own SD cards supply and to test to ensure compatibility with the custom application. Unfortunately, SD cards are increasingly a consumer item and the original SD standard capacity cards are becoming scarcer. Our customer should consider this when securing a supply of SD cards.