Mbed forum

Disco IoT L475 connection to Pelion over WiFi

(Christodoulos Protopapas) #1

Hello everyone,

For the past week I have been trying to connect my Disco board to Pelion with no success.

I have tried 3 different micro SD cards and I tried them before and after formatting them. I have tried 2 different SD card connectors as well. In addition, I used my phone as a hotspot to check it connects to it and I can confirm that the WiFi connection is there. However, when I go to Pelion Device Management I do not see my device listed.

I have tried deleting existing certificates and API keys to start from scratch but still nothing. In the compiler I can see the dev_credentials.c file so that exists as well. Lastly, when I check the SD card on my laptop using an adaptor, I don’t see anything saved on it (however I am not certain if I should actually see anything saved).

Any help is much appreciated as I have tried the tutorial many times already

Thank you,

(javed deshmukh) #2

I am using code from link


How you have connected SD card. is it like this.

refer attachment , i have connected in this way and it is working.

(Christodoulos Protopapas) #3


Thank you for your reply. I have retried it again now and it didn’t work. One note, I am connecting the SD card to 3.3V and not 5V.

Now I am thinking that my connector might be wrong, as it uses SDI and SDO instead of MISO and MOSI. However as far as I know, I can still connect SDI to MOSI and SDO to MISO so it shouldn’t be a problem.

Also I forgot to say that I checked on CoolTerm and I get gibberish. It’s different every time I reset here is sample of three resets:

.¥¥M!..1ÖÿŸ.qã.ß7q.?ç.ãç.ßg.qç.3çç„ç’.ßçç.qçç.#çç3‡çgç.ßç3ç.q3çç.ãçç7ççç1ç.ßç7çç.q’çç1.ã3çççgßçç7ççüqç7çç1?ç’çç3cd!Ðv<.ƒBþA.=!+)!†1.±!§7;ÿŒ÷¨ûCëù.%!Ã!.}!!!¦ßqã.‡.ßçq7ã1.ßç.qç.qg.ã’ç.ßçç.qç’.qç1.ãgçç.ß3çç.qççç.?ç’ççãç1ç’.ß’çç1.qçç1ç.?çççç7ãç7çççüßççç7ç÷q’çç1çÁ11!! %©ÿA.=ûŒ)!†!)¨!ÑŠ“Œ4÷ØûCëùK¥!M!ñ.1Âoó.;.„.ß’q.cç.‡ç.ßç3q3.ã1çŸçç.ßç’.q7ç.ã3ççßçç7.qç7ç.qççç.ã’çç1ß1ç’ç.qç’ççqç3çg.ãççç7gß7ççççðqçç1ç’#çç1ççcd!Ð.<.!ÿA.=¹Ë+.†1Ë*!£7›ÿŒƒÄ·Ôu;ÿ5uŒ’ü

(javed deshmukh) #4

You need 5v For SD card .

to See proper message on coolterm, select baudrate as 115200.

(Christodoulos Protopapas) #5

Excellent, I didn’t know about the baud rate, now I can see things on the terminal, thank you!

However I don’t see how I should use 5V for the microSD? The 4th pin from the left is 3.3V on my board, and my SD connector says 3.3V

(shai feldman) #6

Please check the following link if it can solve your issue :slight_smile:http://langster1980.blogspot.com/2014/01/mbed-sd-card-tutorial.html

(Christodoulos Protopapas) #7


Thanks for your help I managed to connect ,only with my hotspot though. Whenever I am trying to connect using the company’s WiFi I get Error -3011 . The good thing is that I can now get a feeling on how Pelion is which is good enough for now, I have to understand why I get that error though.

(javed deshmukh) #8

Plz provide MAC ID of your Discovery board (WiFi chip ) to your IT team to allow WiFi access in your office network, May be your Office is blocking unidentified WiFi MAC ID