Using ESP32S3 and USB Host framework (C language) to get the right response

[andyparkers]

Is it correct to send data to Radex ONE this way and try to parse measure?

Form and send a new packet:

struct Keys {
    int key_a;
    int key_b;
    int key_c;
    int key_d;
} keys;

void ProcessKeys(uint8_t* input_array) {
    keys.key_a += 0x04;
    keys.key_c -= 0x04;
    if (keys.key_a > 0xff) {
        keys.key_a -= 0xfe;
        keys.key_b += 0x01;
        if (keys.key_b > 0xff) {
            keys.key_b = 0x00;
        }
        keys.key_c -= 0x01;
    }
    else if (keys.key_c < 0x00) {
        keys.key_c += 0xff;
        keys.key_d -= 0x01;
        if (keys.key_d < 0x00) {
            keys.key_d = 0xff;
        }
    }

    uint8_t data[18] = {0x7b, 0xff, 0x20, 0, 0x06, 0, (uint8_t)(keys.key_a),
                        (uint8_t)(keys.key_b), 0, 0, (uint8_t)(keys.key_c),
                        (uint8_t)(keys.key_d), 0, 0x08, 0x0c, 0, 0xf3, 0xf7};

    for (int i = 0; i < 18; ++i) {
        input_array[i] = data[i];
    }
}

Parsing in callback function by the end of the transfer function:

void usb_transfer_complete(usb_transfer_t *transfer) {
    printf("Transfer status %d, actual number of bytes transferred %d\n", transfer->status, transfer->actual_num_bytes);
    ESP_LOGI(TAG, "Enter transfer callback");
    if (transfer->status == USB_TRANSFER_STATUS_COMPLETED) {
        ESP_LOGI(TAG, "USB transfer completed successfully!");
        uint8_t* data = transfer->data_buffer;
        ESP_LOGI(TAG, "Response: %f", ((float)(data[20]) + (float)(data[21]) * 256
                                        + (float)(data[22]) * 256 * 256) / 100.0);
    }
    else {
        ESP_LOGI(TAG, "USB transfer failed with error code %d", transfer->status);
    }
}

Result:

1. All this done according to 'init.py' file, but I get weird values in response, for instance, '107861.3' and '146730.2'. What do I do wrong?
2. Where did you find info about data format? Did you reverse-engineer that?

[luigifab]

Yes, init.py commands are reverse-engineered.
I used the official tool to capture usb packets with Wireshark.

If you can read your device measures with my tool but not with your tool... you probably sent a wrong command.
Suggestion: try to log your commands and my commands to compare them.
Perhaps you must initialize struct Keys, I'm not sure.

[andyparkers]

I provided you with a part of the whole code only, it was initialized beforehand according to init.py. I am wondering how I can log what I get in response, can I just print(hexa)? If I do this, I get:
b'z\xff\x80\x16\x00(\x00\x00\x00&\x80\x00\x08\x00\x00\x0c\x00\x00\x00\x0b\x00\x00\x00\xcdr\x01\x00\x0f\x00\x00\x00 \x0c\x85' for 0.11 µSv/h, so the actual index of hexa[20] is [12] (because B in hex is 11 in decimal), it is like shifted right by 8 elements and I won't get full answer log message. I might assume that this happens due to partial data request since you take 42 bytes only in this line:

elif self.com == 'ONEv1':
	return self.serial.read(12 + 21 + 2 + 2 + 2 + 2 + 1)

but anyway this is weird for me. What about my case: recently I have found out that I can't get any response from MCU and can only send data and it is the same as yours in hid_set_report (successfully anyway, callback function on the end of transfer is called), now I am trying to read the response. If you have any thoughts how to do this, please help me out. In documentation there is a send-only example, so I can send data using usb_host_transfer_submit(), but have no idea how to obtain the response.

[luigifab]

Yes, print(hexa) or print(hexa[20]) are beautify ways.

For the Radex One (ONEv1), if I remember correctly, to get a measure:

• you must send a command to a specific address (I suppose to ask to the device: I would like the read this memory case)
• then you can read the result of the measure (with read(12 + 21 + 2 + 2 + 2 + 2 + 1))

If usb_host_transfer_submit is the equivalent of hid_set_report, you need an equivalent of hid_get_report.

In the documentation, I don't understand anything, perhaps it's that: the peripherals/usb/host/hid example demonstrates the possibility to receive reports from a USB HID device with several interfaces.

[luigifab]

Did you find something?

[andyparkers]

Did you find something?

I might be mistaken, but I found out that you need to write your own driver in case you use a USB host MC for communication with the Radex device. There is no need for this provided you use the Python script, because you install the official driver beforehand, but in case with MC you are empty handed.

[luigifab]

The official driver is not needed for my python script.