MBED+Jumentum Basic and problems using the SD

09 May 2011

Hello,

I am new to MBED and I have succesfully used some of the code examples, but I would like to have some quick offline coding capability and the Jumentun-Soc porting to MBED seems to me a good approach, but I have not been able to use the SD from within Jumentum-Soc, while I have no problem if using MBED libraries. This happens to me with rev 0.99 and 0.99.1, where I get the "MMC7SD absent" status at startup. I have tried with a micro-sd (with the Coolcomponets expansion board for MBED) as well as with an esternal SD socket, but without success, so I dare I am doing something wrong. I repeat that with the MBED libraries and online compilation they work.

So here they go a set of questions that will appreciate if some clever mind can answer:

-Has someone been able to use the SD from Jumentum-soc for Mbed? -I so, which where the signal lines used from the SD to MBED? -What type of SD was used? -Voltage used for the SD? (3v3 or 5V) -Is there some place in Jumentum-soc fro MBED where the SD connections can be configured?.

Thanks in advance,

Jose-Maria

09 May 2011

I forgot another question... What type of format should be used in the 2GB SD (Fat32?, Fat,) and block size? jose-maria

09 May 2011

probably FAT16

09 May 2011

Hi Jose, have you used the correct mbed pins (11, 12, 13 and 14) I had to change the connections in my board and worked OK Regards

10 May 2011

Hello Fabian, Of course not..... The Cool components board use the "other" SPI with 5,6,7,8.

I was expecting something like this. I saw other setups with 11,12,13 and 27 !

I will rework the board and I hope it will work.

Thankyou very much.

Jose-Maria

10 May 2011

Jose: Please drop a line here when your setup works Fabian

11 May 2011

Hi Fabian, Where you also using the CoolComponents board? . Then PCB traces are very thin and the space to do some rework is minimum. Before starting to use the cutter I want to insure that we are talking of the same board.

If not ,I will first remove an SD socket from an old card reader and try to check with it.

It is a pitty that there is no documentation about the hardware configuration defined in the MBED Jumentum Soc basic compilation, specially in this SD area, or at least I have not been able to find where it is defined in the source code and examples supplied with the basic. The only reference I found is the comment that it works fine with the Mbed-Expreso board, that uses pins 5,6,7,8 for the SD, the same as the Coolcomponents board, so I am really confused.

I will keep on investigating, Jose-Maria

11 May 2011

Hi again Jose Maria, I`m using a home-made board, it lets me change almost everything. I tested first the SD with pins 5, 6, 7 and 8 but it doesn't work at all, then I discovered in the source code (sorry I`m not sure in which file it was) the pin assignement for the SD, last I rewired the board and worked OK with an old MMC FAT12 formatted. The other option is to recompìle the code with your prefferences. Let me check again the source code to see where the #defines are. Regards, Fabian

12 May 2011

Hello Fabian, Daniel has given to me a compilation with the SD at 5,6,7,8 and now I can use the SD (there is a problem but I need to undertsand better what the fastftest2.bas demo file does).

Thanks !

Jose-maria