Rust Particle Argon Wifi AT Commands

Firmware
1

Hello,

i am trying to implement WiFi for the Particle Argon in Rust.

I think the esp32 chip is connected via uart to the nrf52. (https://docs.particle.io/assets/images/argon/argon-block-diagram.png) but am not 100% sure.

I tried reverse engineer the cpp code (device-os/esp32_ncp_client.cpp at develop · particle-iot/device-os · GitHub) but could not get a response from the esp32 when i send an AT command there is no response. (Basic AT Commands — ESP-AT User Guide documentation) I just sent a basic “AT\r\n” but get no response.

For uart i used the pins from the layout. I tried to use the rts/cts pins manually and with the provide nrf52 uarte hal.
For the baudrate i used 921600.

Before i started the transmission i set wifi_en and boot_mode high. (I got this from the cpp file)

As of now i tried a lot of different parameters but cannot get a response from the esp32. I tried uart with an external device and sending and receiving data works fine there.

Regards
Sebastian

2

Can you show your code?
Serial1 is not the UART you’d use to talk to the NCP.

However, it would be a nice feature request to implement a WiFi.command() API à la Cellular.command()

3

Here is the rust code. (Just test code at the moment)

I thought it would be serial as it is initialized here:

5

Hi,

I kind of have the same issue trying to bootstrap the communication. It seems @heusini uses the proper pins, is it maybe that the UARTE is not capable of directly speaking to them?

Cheers

7

This is the code I used to test communicating with the ESP32 from Device OS. I was able to send AT commands and get responses with this.

    // Disable ESP32. It appears to be turned on by default even in SEMI_AUTOMATIC mode
    WiFi.off();
    delay(5000);

    // Enable ESP32
    _log.trace("rebooting ESP32");

    pinMode(ESPBOOT, OUTPUT);
    pinMode(ESPEN, OUTPUT_OPEN_DRAIN);
    digitalWrite(ESPBOOT, 1);
    delay(100);
    digitalWrite(ESPEN, 0);
    delay(100);
    digitalWrite(ESPEN, 1);
    delay(100);

    // Set up serial
    _log.trace("Starting serial");
    Serial2.begin(921600, SERIAL_FLOW_CONTROL_RTS_CTS); // 115200
1 Like
8

Thanks for testing.
So if you do Serial2.write(“AT”); you get “Ok” when you do Serial2.read();

9

You do need an \r\n after the AT command because you need a line terminator, and the OK is uppercase, but yes. It might take a couple tries after rebooting the ESP32. I had a loop of up to 4 retries.

1 Like
10

Thanks for the help. I could fix it. I selected the wrong pins :man_facepalming:
I used P1.04 as TX and P1.05 as RX and so on. I marked the pins in the image so maybe it helps someone in the future :slight_smile: Such a silly mistake…
2021-03-31_10-54

2 Likes
11

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