Hi，When I tried to connect ESP8266(WIFI) to Beablebone Black via UART4,I found that I

Scott_Li · September 29, 2015, 3:15am

Hi，When I tried to connect ESP8266(WIFI) to Beablebone Black via UART4,I found that I couldn’t read any data from the UART4’s RX pin.And I made a test,the UART can communicate with the USBtoUART line that is based on PL2303 IC.Now,I get my conclusion，The UARTs who have the same TTL voltage(3.3v vs 3.3v) can‘t communicate with others，but the different(5v vs 3.3v) can do it.I am very confused.Who can help me

Przemek_Klosowski · September 29, 2015, 3:28am

That is unlikely—are you sure that you’re using CR+LF line terminator? ESP8266 seems to need both.

Scott_Li · September 29, 2015, 4:36am

@Przemek_Klosowski
Yes,the UART4 of BBB could not even receive the initialization information of the ESP8266(a lot of messy codes + ready).But the USBtoUART line(PL2303 5V TTL voltage) can do this

Samuel_Bucquet · September 29, 2015, 5:03am

@Scott_Li As I plan to use the esp8266 as a remote debug line and reset switch for the BBB, I am very interested in the topic. Did you try another UART on the BBB, like UART0 ?

Samuel_Bucquet · September 29, 2015, 5:06am

@Scott_Li What firmware did you try ? I look on this one : https://github.com/jeelabs/esp-link.
Maybe for tests purpose it can be enough.

Scott_Li · September 29, 2015, 5:30am

@Samuel_Bucquet
Yes,I tried all the UART,but it’s not worked.Now I haven’t solved the problem.

Samuel_Bucquet · September 29, 2015, 5:36am

@Scott_Li maybe I’ll try this week. I’ll let you know.

Scott_Li · September 29, 2015, 5:45am

@Samuel_Bucquet Ok,if I solved the problem，I’ll tell you.Now I am using the 1.01 firmware of http://ai-thinker.com

Giligain_I · September 29, 2015, 6:00am

(•,•)
Following topic.

Samuel_Bucquet · September 29, 2015, 5:52pm

@Scott_Li OK, I tried this afternoon and I succeeded to boot the esp8266 and I saw the console. I connected only 3.3v GND TX and RX directly on the bbb 3.3v GND AND P9_24 and P9_26 (UART1) BUT I didn’t succeeded in sending anything to the esp8266 but I was able to see the garbage at boot and the ‘ready’ line. Good luck.

Scott_Li · October 14, 2015, 6:38am

@Samuel_Bucquet
Hi，I tried it again.the result is the same as yours.And not solved,I think I’ll change to other hardwares.

Scott_Li · October 14, 2015, 9:16am

@Samuel_Bucquet For the last try,I updated the firmware to Ai-Thinker SDK 1.2, and then I found all the things were OK.Now I can send AT commend and receive “OK”.

Samuel_Bucquet · October 14, 2015, 9:18am

@Scott_Li hi, I stopped working on it at the moment as I fried my two boards. Thank you for keeping me posted.

Samuel_Bucquet · October 14, 2015, 9:22am

@Scott_Li I succeeded flashing esp-link v2 on one board from the BBB.
But after the flash the WiFi was very hazardous. So I decided to power it not from the bbb and I fried the olimex board !

I think we can work the esp8266 broads from the bbb, it’s just that I’m not very apt to this things (I’m more a software guy). As soon as I received my new boards, I will retry.

Scott_Li · October 14, 2015, 10:02am

@Samuel_Bucquet I’m also a software guy.Did you use the minicom to debug the ESP8266?if yes,try writing C code to debug it.

Samuel_Bucquet · October 14, 2015, 10:05am

@Scott_Li no I just use ‘screen’ to access the serial console on the esp8266. And it worked well till I fried the board. The firmware I flashed on the other hand, I can’t tell if it was a hardware or a software issue.