Esp-idf: [TW#12192] ESP_BT_MODE_BLE mode support

[lucashutchinson]

Hi All,

If I call the esp_bt_controller_enable function with the argument ESP_BT_MODE_BLE it will return an error of ESP_ERR_INVALID_ARG

error = esp_bt_controller_enable(ESP_BT_MODE_BLE);

The call used in all of the esp-idf examples seems to initialise with ESP_BT_MODE_BTDM
error = esp_bt_controller_enable(ESP_BT_MODE_BTDM); which works.

However this is the BT classic + BLE mode, which in my use case is not needed.

Is the ESP_BT_MODE_BLE mode not yet supported by the IDF?

[igrr]

Yep, it's not supported, as the doc says:
https://github.com/espressif/esp-idf/blob/dca0377e19c6e514c0c694b521c3495a6d46c3af/components/bt/include/bt.h#L64

[lucashutchinson]

Ah right,
Sorry for not thoroughly checking through the docs.

Any idea on when support for this might be added?

[TianHao-Yoursmake]

@lucashutchinson , this will be added. But it need much work to do.

[benjaminaigner]

I would like to have this feature too, plz add :-)

[jkhax0r]

I'm curious how this helps over the dual mode where you just don't use classic? Is it just an optimization to turn off the classic mode, so is there lower power, less memory, less code, etc...?

[benjaminaigner]

@jkhax0r Basically it's power consumption

Edit: at least in my case :-)

[MrSurly]

Also, esp_bt_controller_enable(ESP_BT_MODE_IDLE) doesn't work (returns an error) -- is it possible to put BT back into idle? Or the state it was in on power-on?

I'm working on Bluetooth.deinit() for MicroPython.

[e7p]

@MrSurly esp_bt_controller_disable(ESP_BT_MODE_BTDM); seems to work, but it doesn't disable all of the hardware, so it is still decently drawing current.

Edit: just checked, these are my results with my own prototype module featuring an ESP-WROOM32 and some additional hardware (which should take around 20mA additionally. So only measuring the WROOM32, you can subtract around 0.020 A from each value):

current @ 5V | when
------------ | ----------------------------------------------------------
0.056 A | while flashing via serial
0.084 A | idle (prior to any bluetooth functions)
0.100 A | after esp_bt_controller_init called
0.170 A | after esp_bt_controller_enable(ESP_BT_MODE_BTDM) called
0.094 A | after esp_bt_controller_disable(ESP_BT_MODE_BTDM) called
0.094 A | after esp_bt_controller_deinit called

So no, currently no possibility seems to exists to put the ESP32 back into the state it was in on power-on. Please correct me and let me be wrong, because it would be good to be able to put it back to the state suited best for power saving.

[MrSurly]

@Endres Thanks, I didn't even see esp_bt_controller_disable, I just assumed that ESP_BT_MODE_IDLE was the right way to shutdown BT.

So no, currently no possibility seems to exists to put the ESP32 back into the state it was in on power-on. Please correct me and let me be wrong, because it would be good to be able to put it back to the state suited best for power saving.

That's too bad, I agree, it would be good. Let's hope it's implemented soon.

As a side question, does a cold reset return the hardware back to lower power consumption?

[e7p]

As a side question, does a cold reset return the hardware back to lower power consumption?

No, after a reset initiated by esp_restart, I am around the same current (0.093 A) as after esp_bt_controller_disable(ESP_BT_MODE_BTDM).

After a hard reset (EN pin) though I am at the "idle" current again.

[TianHao-Yoursmake]

@MrSurly , the bluetooth powersave has not start yet. So the current is not good. Powersave is in schedule.

[MrSurly]

@TianHao-Espressif Thanks for the information.