- Wed Apr 10, 2019 7:59 pm
#81682
> > ... just to make this thing work as advertised?
>
> why, what was advertised?
To be able to control a relay over a wifi connection.
Ok, the story so far...
What I've done is take a PL2303TA USB to TTL-level serial convertor and connect it directly to one of my ESP8266 modules.
The PL2303TA (which I had from a previous project - to flash a new bios into a DOCSIS cable modem) looks like a thumb drive with a cable coming out the back end. The cable is terminated with 4 wires - each wire has a socket into which a pin can be inserted. The PL2303TA seems to output 3.3v compatible signals but it sends out +5V power on it's red wire, but that is easily changed by opening it and moving the red wire from the 5v pad to the 3.3v pad. I connected the TX wire to the RX pin on the 8266, and the RX wire to the TX pin on the 8266.
There are drivers for the PL2303TA that you have to go out and find - Windows 7 does not automatically see the convertor or find drivers for it. It becomes a serial port (com 5 in my case).
I then went out and downloaded a terminal emulator (Termite 3.4) and set it to use com 5, 115200 baud, No parity, 8 data bits, 1 stop bit.
I note that I came across the following from somewhere:
--------------
On reset, ESP8266 hardware default baud rate depends on the crystal choice. With a 40MHz crystal you get 115200bps. With a 26MHz crystal you get proportionally less, 74880bps (115200*26/40). Almost everyone (including Espressif) ships hardware with a 26MHz crystal, so almost everyone gets 74880bps by default.
---------------
My 8266 board has 26 mhz oscillator and the above information is wrong for my 8266. A baud rate of 74880 (which I tried) would result in garbage characters. But a baud rate of 115200 works perfectly.
Also note: Initially I was getting ERROR sent back from the 8266 to everything I sent using the Termite program, but then I went to Termite settings and set the APPEND function to CR-LF (ie - send CR+LF when I hit return). It had been set to just one of them, not both.
The following is copied directly from the Termite terminal program:
------------------
AT+GMR
AT version:1.3.0.0(Jul 14 2016 18:54:01)
SDK version:2.0.0(5a875ba)
v1.0.0.3
Mar 13 2018 09:35:47
------------------
AT+CIFSR
+CIFSR:APIP,"192.168.4.1"
+CIFSR:APMAC,"be:dd:c2:26:38:cc"
OK
------------------
AT+CWMODE?
+CWMODE:2
------------------
AT+CWLAP
ERROR
------------------
AT+CWMODE=3
OK
(Now I see list of SSID's.)
------------------
I've been able to connect the 8266 to my office wifi network and can ping it from a remote PC. I've tried some AT commands that are supposed to work with the GPIO pins (like AT+SYSGPIO) but the commands I've tried so far just give me ERROR. It would be nice if a command like "AT?" would give me a list of the AT commands that any given 8266 module understands.
And since nobody has spoken up here, I have to assume that the stock firmware that these things come with don't offer a simple web-based interface to do what I'm doing now through the serial port through these AT commands (like change the wifi mode, connect to a network, etc) or to control the state of the GPIO pins.
>
> why, what was advertised?
To be able to control a relay over a wifi connection.
Ok, the story so far...
What I've done is take a PL2303TA USB to TTL-level serial convertor and connect it directly to one of my ESP8266 modules.
The PL2303TA (which I had from a previous project - to flash a new bios into a DOCSIS cable modem) looks like a thumb drive with a cable coming out the back end. The cable is terminated with 4 wires - each wire has a socket into which a pin can be inserted. The PL2303TA seems to output 3.3v compatible signals but it sends out +5V power on it's red wire, but that is easily changed by opening it and moving the red wire from the 5v pad to the 3.3v pad. I connected the TX wire to the RX pin on the 8266, and the RX wire to the TX pin on the 8266.
There are drivers for the PL2303TA that you have to go out and find - Windows 7 does not automatically see the convertor or find drivers for it. It becomes a serial port (com 5 in my case).
I then went out and downloaded a terminal emulator (Termite 3.4) and set it to use com 5, 115200 baud, No parity, 8 data bits, 1 stop bit.
I note that I came across the following from somewhere:
--------------
On reset, ESP8266 hardware default baud rate depends on the crystal choice. With a 40MHz crystal you get 115200bps. With a 26MHz crystal you get proportionally less, 74880bps (115200*26/40). Almost everyone (including Espressif) ships hardware with a 26MHz crystal, so almost everyone gets 74880bps by default.
---------------
My 8266 board has 26 mhz oscillator and the above information is wrong for my 8266. A baud rate of 74880 (which I tried) would result in garbage characters. But a baud rate of 115200 works perfectly.
Also note: Initially I was getting ERROR sent back from the 8266 to everything I sent using the Termite program, but then I went to Termite settings and set the APPEND function to CR-LF (ie - send CR+LF when I hit return). It had been set to just one of them, not both.
The following is copied directly from the Termite terminal program:
------------------
AT+GMR
AT version:1.3.0.0(Jul 14 2016 18:54:01)
SDK version:2.0.0(5a875ba)
v1.0.0.3
Mar 13 2018 09:35:47
------------------
AT+CIFSR
+CIFSR:APIP,"192.168.4.1"
+CIFSR:APMAC,"be:dd:c2:26:38:cc"
OK
------------------
AT+CWMODE?
+CWMODE:2
------------------
AT+CWLAP
ERROR
------------------
AT+CWMODE=3
OK
(Now I see list of SSID's.)
------------------
I've been able to connect the 8266 to my office wifi network and can ping it from a remote PC. I've tried some AT commands that are supposed to work with the GPIO pins (like AT+SYSGPIO) but the commands I've tried so far just give me ERROR. It would be nice if a command like "AT?" would give me a list of the AT commands that any given 8266 module understands.
And since nobody has spoken up here, I have to assume that the stock firmware that these things come with don't offer a simple web-based interface to do what I'm doing now through the serial port through these AT commands (like change the wifi mode, connect to a network, etc) or to control the state of the GPIO pins.
