Thank you. I think EspressIF needs to weigh in here. Both their documentation and even this thread contains wildly different and contradictory information. Some places say that the external clock should connect to XP, others to XN. Some way less than 1V, some say more than 1v7. Some suggest you ...

Would someone at EspressIF please provide up-to-date information regarding how to connect an external 32.768kHz oscillator to the ESP32 (I'm using the ESP32-WROOM-32E) and the software configuration for using it (ESP-IDF) for the RTC?

I am using an external TCXO that produces a 3v3 square wave ...

The documentation shows that it is safe to call gpio_intr_disable() from an ISR if CONFIG_GPIO_CTRL_FUNC_IN_IRAM is enabled, but does not have the same note for gpio_intr_enable(). I see no difference in their code and haven't seen any issues when using it, but I'd like to be sure. Does anyone know ...

Hi Pauly,

Yes, the PSRAM is recognized and working in my development boards. My reading also suggested that the PSRAM is internal to the SoC. I had not yet removed the shield, but that was my next step, so thank you for having done that and confirmed it! I have enabled PSRAM in sdk config and have ...

I would like to use the ESP32-WROOM-32E-N8R2 (8MB SPI Flash, 2MB PSRAM) in the next version of a product.

The datasheet makes it clear that IO16 is reserved for the PSRAM CS.
Unfortunately, it doesn't specify which pin is used for PSRAM SCLK.

In the SDK configuration, when configuring PSRAM for ...

Thanks for the suggestion; I added the following to the esp_ping_thread()

if (ep->on_ping_end) {
// Check stack usage
UBaseType_t uxHighWaterMark;
uxHighWaterMark = uxTaskGetStackHighWaterMark( NULL );
ep->on_ping_end((esp_ping_handle_t)ep, (void *)uxHighWaterMark);
}


Then printed the ...

Using ESP IDF 5.4.1 and esp_modem with the esp_ping reference code. The default ping task stack size using ESP_PING_DEFAULT_CONFIG() is 2.5K and with that stack size, I frequently get exceptions on ping_end (as the stack unwinds). Increasing the stack size to 4K completely eliminates the exceptions ...

Something to be aware of:
The ESP32 r1 and r3 require different loading for the crystal oscillator.
I use a 6pF 3.2x1.5mm 2-SMD crystal with two loading caps, all located close to the XO pins and following good layout practices.
My older boards built with ESP32 r1 require at least 10pF load ...

Is there an API to access the last exception address(es) or backtrace(es)?
This would be incredibly helpful for debugging remote equipment in the field so that after a reset, it could report not just the reason for reset, but the address(es) or backtrace(es) indicating where the exception took place.

For anyone else who encounters this, it turned out to be pilot error: accessing the SPI bus from both interrupt and user contexts.

The light sleep being enabled was a red herring, it simply affected timing. I use the SPI bus to manage a radio transceiver extensively in interrupt context and ...