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For the flow control, I did not know how to configure it. The software asked me to try other baud rates and to enable flow control, so I tried all the possible different baud rates, and it did not work. It recognised the port but could not connect to it. I also tried using an AT command tester for Simcom modules from the website, but the software was unable to connect to the USB port ( Picture 3: error from the AT command tester). I have tried typing AT commands ("AT" and "ATE1") directly on Putty (I did not hit Ctrl-C to break to the Python REPL), but I received an error message saying that Putty does not recognise the AT command ( Picture 2: error with Putty) When powered on, the module’s LED switches on so I know that my python code can communicate correctly and that the problem occurs for AT commands only. The “Read_buffer” function (see code below in picture 2) that reads the command in the buffer by sampling the UART returns an empty string.īefore sending the AT commands, I powered the module on and off to boot the modem using the Pin(14) of the SIM7020E module.It looks like the SIM7020E module does not receive the AT command and does not respond to it (I should receive the response “OK”). After sending an AT command (“AT” and “ATE1”), uart.read reads ‘b\x00’ and not the AT command.The issues I have with the code are that: #Read in the buffer by sampling the UART until timeout # Read and return the response (until timeout) I have copy-pasted a portion of the code here: #Send an AT command - just return the response
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The main functions I utilised to send AT commands are “uart.write”, “uart.any” and “uart.read”. To send different AT commands to configure the modem and set up the APN, I used Micro Python and copy pasted the Python code into Putty (after doing ctrl C, ctrl E and ctrl D to run the code). I fitted the Raspberry Pi Pico into the SIM7020E module using header pins: a picture of the setup is given through this link ( Picture 1: Hardware setup). I am using a RPi Pico, a NB-IoT SIM7020E Module from Waveshare and a Twilio Super SIM card.
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