C-APIs for CMUX manual mode are not working. (IDFGH-9260)

[mallaprashant]

I am currently working on SIM7600 and I am trying to use CMUX manual mode C-APIs but not able to enter CMUX manual mode.

[mallaprashant]

@david-cermak when I use these ESP_MODEM_MODE_CMUX_MANUAL, ESP_MODEM_MODE_CMUX_MANUAL_EXIT, ESP_MODEM_MODE_CMUX_MANUAL_SWAP, ESP_MODEM_MODE_CMUX_MANUAL_DATA, ESP_MODEM_MODE_CMUX_MANUAL_COMMAND, I am getting error on esp_modem_set_mode() function but I can use cmux , command and data mode

[david-cermak]

Hi @mallaprashant

Could you please describe which transitions don't work? Please note that not all transitions withing CMUX_MANUAL are allowed (e.g. not possible to combine with auto mode), and not all devices support all transitions (e.g. A7670 fails to exit CMUX_MANUAL mode).

I've just tested basic transitions and they seem to work. Used the default pppos client, but instead of switching to DATA_MODE here:

https://github.com/espressif/esp-protocols/blob/0e215b118f6302fe0d3109a373b248a1ccb6ff00/components/esp_modem/examples/pppos_client/main/pppos_client_main.c#L261-L265

Switched to CMUX_MANUAL with:

    err = esp_modem_set_mode(dce, ESP_MODEM_MODE_CMUX_MANUAL);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "esp_modem_set_mode(ESP_MODEM_MODE_CMUX_MANUAL) failed with %d", err);
        return;
    }
    err = esp_modem_set_mode(dce, ESP_MODEM_MODE_CMUX_MANUAL_SWAP);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "esp_modem_set_mode(ESP_MODEM_MODE_CMUX_MANUAL_SWAP) failed with %d", err);
        return;
    }
    err = esp_modem_set_mode(dce, ESP_MODEM_MODE_CMUX_MANUAL_DATA);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "esp_modem_set_mode(ESP_MODEM_MODE_CMUX_MANUAL_DATA) failed with %d", err);
        return;
    }

Then waited for the mqtt to publish/subscribe and instead of going back to the COMMAND_MODE here:

https://github.com/espressif/esp-protocols/blob/0e215b118f6302fe0d3109a373b248a1ccb6ff00/components/esp_modem/examples/pppos_client/main/pppos_client_main.c#L289-L293

Used manual exit (plus sending some AT command to benefit from CMUX)

    err = esp_modem_get_imsi(dce, imsi);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "esp_modem_get_imsi failed with %d", err);
        return;
    }
    ESP_LOGI(TAG, "IMSI=%s", imsi);
    err = esp_modem_set_mode(dce, ESP_MODEM_MODE_CMUX_MANUAL_COMMAND);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "esp_modem_set_mode(ESP_MODEM_MODE_CMUX_MANUAL_COMMAND) failed with %d", err);
        return;
    }

And everything works as expected.

I'd suggest using the modem_console example to exercise with the manual mode, the actual state and your device interaction.

[mallaprashant]

@david-cermak Thanks for the reply. I am working with SIM7600EI. After creating DCE and sending some AT commands . I tried to transit to CMUX_MANUAL mode. I am getting this error (ESP_ERR_NOT_SUPPORTED). But the transitions between COMMAND to DATA and COMMAD to CMUX works fine.

[david-cermak]

Oh, I think I understand now. you're using the latest version of esp-modem from component registry (0.1.25 as of now) is that correct? The manual CMUX mode support was added after that and we haven't bumped the version number yet, I'm sorry.

As a workaround, you can use the latest version from this repository and add it as a local dependency using EXTRA_COMPONENT_DIR. (I'll also increase the version number at the earliest opportunity)

[mallaprashant]

@david-cermak thanks for the update. I tested new version of esp_modem and it worked.

[lucle-bonboncar]

I am devloping with EC800 module, this is not support CMUX, so when I switch between DATA and AT mode, device have lost connection with the server, MQTT client is disconnected, any advise on that, how to avoid disconnected with server when transition from DATA mode to AT mode?

I have trying to using ESP_MODEM_MODE_CMUX_MANUAL but it looks like doesnt work