UPDATE:
I figured the problem was with the connection over the PL2303. I reduced the BAUD rate of ESP to 9600 bps with help of an Arduino. Contacted the manufacturer of PL2303 and will update the post with the instructions when I receive them.
I'm trying to get an ESP-201 (variant of ESP8255) to work on Windows host. My aim is to configure the setup correctly and valitade by geting an OK response for AT command.
I've read that PL2303 PC-side default baud rate is 9600 and ESP-201's baud rate is 115200. I've suspected that data I'm sending isn't received correctly by ESP so I tried to configure the BAUD rates. I tried do it with Python because PuTTY connects to the device but doesn't let me give any input to the terminal. So I've tried to run this Python code, without the ESP connected to the PL2303.
import serial
esp = serial.Serial(port="COM5", baudrate=9600, timeout=1)
esp.write(b"PLBAUD 115200")
time.sleep(500)
print(esp.readline())
esp.write(b"BAUD 115200")
time.sleep(500)
print(esp.readline())
This should first set the ESP side BAUD rate of PL2303 to 115200 then set the PC side BAUD rate to 115200. But sending the AT command with the following code doesn't yield the expected OK response after changing BAUD rate setting in Windows device manager BAUD settings and plugging in the ESP module.
import serial
esp = serial.Serial(port="COM5", baudrate=115200, timeout=1)
esp.write(b"AT\r\n")
print(esp.readline())
Incase the strings sent are in UTF-8, I encoded them to hex manually and sent them again and result didn't change.
I've contacted Waveshare, maker of this module, and learned that the host PC and the device on the TTL side of this adapter must have the same BAUD rate in order to work. Set them both back to 115200 and it is solved.
This is due to the adapter not having a buffer that adapts the BAUD rate, rather than it being a pass-through device.
Related
I am writing some code for my arduino nano and I am using an HC-05 module for wireless transfer of data. I am sending my data as such. This is from the serial monitor, using a usb and regular print statements. I want to be able to recieve this data, and the store it in a csv (I know how to store incoming data). I need help recieveing my data.
22:17:46.765 -> =============================================================
22:17:47.770 -> Sleep timer:242
22:17:47.770 -> Light Sleep: 0 Deep Sleep: 0
22:17:47.805 -> Total Light Sleep: 0 Total Deep Sleep: 0
22:17:47.838 -> Total Sleep: 0
22:17:47.871 -> =============================================================
For some reason, when I connect my HC-05 to my windows desktop via bluetooth, and open a serial monitor in com ports 3 or 4, I get no read out.
My ports
I have it set up as so.
My wireless intialization
Then, I use
MySerial.print()
, to send data, yet I get no output, same thing occurs if I use
Serial.print()
.
I tried getting a new HC-05 module, Switched out all the hardware, tried different prints including Serial and MySerial. I though i could get an output.
Python code I tried to use python to extract the data, yet I get no output. I am not sure what to do here.
Not enough information, but I'll answer biased on the experience I've had with these modules.
Here are instructions for changing or verifying the baud rate on the module:
https://www.instructables.com/Change-the-Baud-Rate-of-HC-05-Bluetooth-Module-Usi/
For my module, I could just send AT commands by default without putting it into AT mode. Send 'AT' to the module and it should respond with "OK".
It helps a ton if you have an ftdi cable for troubleshooting. Connect the ftdi to the HC-05, verify the baud rate and that the HC-05 is responding, open a serial monitor for the bluetooth on the pc and one for the ftdi cable. Try sending data back and forth. Also, be 100% sure you're using the correct com port for your bluetooth by unpairing and repairing and see which com port shows up.
It actually is possible to use the HC-05 for programming the Arduino as well if you set the baud rate to 115200 and figure out a way to hit reset on the Arduino as soon as the bluetooth connects(status/state goes solid). I used an ATTiny for that, but you could just use a pin on the nano connected to reset and another pin to monitor the "state" pin which is connected to the led on the HC-05. That way you can have wireless data and wireless programming if you wanted that.
So I have succesfully attached a Esp8266 to an Arduino Due. I can communicate with it via Serial Monitor if I choose the Baudrate to be 74880. Then all the commands come to it correctly and can be read back correctly. However, when I send the command AT+RST which restarts the Esp8266 I can no longer communicate with it and need to reopen the serial connection with a Baudrate of 115200. I have to repeat this every time I load the code new to the Arduino or when I power off the Esp8266.
Any ideas where this behaviour comes from?
Here you are an explanation about where are the origins of such a behavior:
Baudrate of 74880 Bd is ESP's 'native' baud rate for sending debug messages generated automatically by the system itself during the boot in case there is 26 MHz instead of 40 MHz crystal used on board - and as we can see, mostly that is the case.
With 40 MHz crystal the baudrate would be as expected (115200) but with 26 MHz crystal instead, baudrate is 115200 * 26/40 = 74880.
Later after bootloader ends baudrate is controlled in other way so that's why you have two different baudrates - the first is the default one (74880) and the second is the one that is active later (the one you can set).
I usually set baudrate to 74880 so I can see both the messages generated automatically and the messages I send from the code.
In order to set UART baudrate persistent after a reset you should use AT+UART_DEF.
From the AT instruction :
AT+UART_DEF – default UART configuration This command sets the UART configuration and save it to flash. It is stored as the default
parameter and will also be used as the default baudrate henceforth.
I get strange encoded messages from my sim900 module when I enter AT commands. I have set the baud rate to 9600. I've tried using several terminals but to no avail.
Any help is appreciated.
Thanks
I am quite sure the issue is with baud rates. Your terminal baud rate should be set to the baud rate of the module. There can be one of the followings issues with your setup
Your sim900 module is set to another baud rate (try 115200)
You are not sending \r at the end of your commands
Your sim900 is in auto-baud state and is waiting for AT\r command to lock in to the baud rate you are communicating in. In this state you need to send AT in uppercase a few times after the modem switches ON.
Problem: How to access a device whose baud rate is 921600 from Windows 7 PC.
I have an embedded device and I used to connect to this device through USB Serial Port at a baud rate of 115200.
Now, the embedded device's baud rate is changed to 921600. I cannot communicate with this device.
I have a terminal program (Teraterm) in which I can set the baud rate to 921600. But I am not able to communicate with the emb device as the maximum baud rate that can be set in Windows 7 device manager for this device is 128000.
I even tried with a Python script (changing baud rate 921600) which was working earlier (at baud rate 115200). Now it's not working.
I am using a EVB for siemens MC45 GSM modem. Itried to send At commands to it via serial port with Hyperterminal in windows (both Xp and 7). But the hyperterminal window is showing that I am connected but when I type something it doesnot show my writings. and no response from the GSM modem is received.
What Can I do ?
The problem is with your hyper terminal settings when you are connecting with the modem.
Use these settings: Baud rate:9600 data bits:8 stop bits:1 parity bits: none flow control:none Should work now. Also check whether you are communicating with the correct port
Have you configured the hyperterminal session properly? I think you will probably need to set it up as follows:
BaudRate 19200
Databit 8
No Parity
Stopbit 1
No Flow control