Thanks - that’s really helpful. Makes sense now.

I'm using a PDM microphone - https://media.digikey.com/pdf/Data%20Sheets/Ole%20Wolff/OWMMOD-403010A-S261F.pdf

This has a clock pin and an L/R pin.

When I'm setting up the GPIO pins - I don't see any way to specify the L/R pin.


typedef struct {
gpio_num_t clk; /*!< PDM clk pin, output */
union ...

Turns out this was being caused by an issue on my side.

I'm having an issue with using SD Cards with SPI
I'm not sure how to track this issue down - I can't recreate it in a simple test program, only in my main application.

I'm confused by what should be passed in the argument for ulp_run

I've seen examples that show this:

ulp_run((&ulp_entry - RTC_SLOW_MEM)/4);

and this

ulp_run(&ulp_entry - RTC_SLOW_MEM);

In the docs it does say that it should be expressed in 32 bit words - which I think is where the /4 is ...

For anyone looking for a working hsp_hf I've pulled together something that works using: https://github.com/bluekitchen/btstack

It's very much based on their demo code with a very small amount of cleanup and addition of microphone input so it fully works.

https://github.com/atomic14/esp32-hsp-hf

I'm trying to run the esp-idf hfp_hf example examples/bluetooth/bluedroid/classic_bt/hfp_hf

It seems to work, but disconnects after a short period of time. This is what I see in the logs:

hfp_hf> con
connect
W (6571) BT_APPL: HF Client found collision (ACL) ...
hfp_hf> I (14101) BT_HF: ESP_BT ...

Looks like I should be using `spi_device_polling_transmit`

Hi All,

I'm trying to control a dual DAC converter using SPI - the MCP4822 (https://ww1.microchip.com/downloads/en/DeviceDoc/20002249B.pdf)

I was hoping to be able to send out 2 samples at around 20KHz but seems to be only able to get about half that rate. I thnk each sample needs to be sent as a ...

I can't find many (any) details on the output drivers.

I thought that unless there are protection diodes that would take the voltage back to the supply rails you should be safe pulling up an open-drain output to a higher voltage as it won't be connected to anything when the output is off?