Connection to UART for a beginner

Antoine Wajntraub · ‎2016-08-10

Posted on August 10, 2016 at 14:14

Hello everyone !

I'm sorry about those dumb questions, but I just began my internship 2 days ago in a company that wants to work with the SPWF01SA module. They gave 2 boxes and no explanation. And the guy who used to work on it left. So I'm alone with that...

In one of those boxes, there is a Silica Branca board, an eval board for the module. I followed the guide

http://www.emcu.it/WiFi/WiFi-QuickStartGuide/WiFiQuickStart.html

but something doesn't work, and I don't know why. My computer recognizes the card as a COM device, and I can connect it thanks to Tera Term. But that's it. Once it's connected, I don't have any message, and when I try to send the ''AT'' command, it doesn't respond. It doesn't respond at any command. I tried with Putty and Termite, same problem. But with Termite, sometime, I have a bunch of ''[00]'''s that look like it's sent by the card. Sometimes I have 2 or 3, sometimes I can have hundreds of them. And that's everything I can get from that card.

In the other box, I have another board, a home-made one. The company has its own board, and integrates the Wifi module on it. The engineer who left soldered some wires directly on the wifi module. There are on GND, RXD1, TXD1 and BOOT0. In the same box, I have 2 cables

http://www.ftdichip.com/Support/Documents/DataSheets/Cables/DS_TTL-232R_CABLES.pdf

. So, I guess, he wanted to connect directly the module to his computer through that TTL/USB cable, right ? Could I have an UART connection like that ? If yes, should I solder some wires to CTS1 and RTS1 ?

Thanks for your answers, and sorry for the beginner questions, but my coworkers can't answer me, and I'm on my own now...

Regards,

Antoine

Gerardo GALLUCCI · ‎2016-08-11

Posted on August 11, 2016 at 13:03

Hi,

box #1: be sure boot pin is floating. Only power/tx/rx jumpers need to be present.

box #2: cts/rts are not needed. In a minimal setup, only 3 pins (gnd, tx and rx) are needed.

Antoine Wajntraub · ‎2016-08-11

Posted on August 11, 2016 at 14:25

Hi,

So I checked, and rechecked, and tested what you said, and even by doing that, that doesn't work, for both cards.

For the box1, the jumpers are where the should be, and only there, and no response.

For the box2, the wires are on the right pins, but no response either. But I don't understand, why don't we need the VCC pin ?

I even tried with a another module, without any board, that I found and that was on a anti-static bag and that looked unused. The solders were done by a guy who knows what he does, and whe tried it with a software that named ''Saleae Logic''. With that, we could see the signal that was sent/received on every pin, because it is connected directly to the wires. When we send the ''AT'' command, we clearly see that the card received : ''AT\r\n'', but nothing appears about the answer. It doesn't send anything back...

Gerardo GALLUCCI · ‎2016-08-23

Posted on August 23, 2016 at 21:12

Do you see starting WINDs after reset/poweron?

I mean WINDs till WIND:0:console active (WIND:1 and WIND:13)