It was the last parameter in esp_ble_gatts_create_service: But I've since switched to the new "database"-based API where you don't have the number of characteristics any more.

Hi josmunpav, did you try running your application on a single core only? (make menuconfig -> Component Config -> FreeRTOS -> Run only on 1st core) I also have sporadic problems with writing to flash memory (crash with IllegalInstruction exception, or a core hangs) but could solve it temporarily by ...

Hi, correct me if I'm wrong, but it seems there's no way to abort a running over-the-air update, for example if a write fails: - just calling esp_ota_begin again will leak memory and crash the application after a few re-tries - calling esp_ota_end doesn't release the memory if the secure bootloader ...

And some additional information on the antenna in the reference design:

This seems to be called an "inverted F antenna", see for example here: http://www.ti.com/lit/an/swra117d/swra117d.pdf

And the wikipedia article: https://en.wikipedia.org/wiki/Inverted-F_antenna

It seems the matching network is a "tapped capacitor" circuit. According to the formula on this web page, the circuit transforms the input impedance (in parallel to the inductor) down by a factor of about 2.6: http://analog.intgckts.com/impedance-matching/tapped-capacitor-matching/ So, if the target...

Hi, I'd like to connect an external antenna to the ESP32 but am not sure how to implement the impedance matching. Basically, I'd like to know the impedance of the chip's RF pin. The hardware design guidelines document specifies in section 3.2.4.1, "RF", that the "...characteristic RF impedance must ...

Hi, I noticed sporadic issues in a project where I use the mbedTLS functions to connect to a web server with HTTPS, such as blocking mbedtls_ssl_handshake or errors in subsequent read/write operations (e.g. -0x7880). (Well, not really sporadic - it failed about 50% of the time ;-) By trial-and-error...

Hi Greenja, good point :) Indeed, the code on the STM32F767 was run without RTOS. However I need to disappoint you - I've repeated the test with the code running in a FreeRTOS task on the STM32F767 and the numbers are still more or less the same. Attached is the assembly output of the compiler. The ...

Hi Angus,

attached is the test code. Let me know if you need more information or other files.

cheers
Andreas

I also wonder about these points. About your last question, I noticed a few things: The "GATT server" example uses the same UUID for the service and the call to esp_ble_gatts_app_register. However, there's a restriction on the UUID you can send to the esp_ble_gatts_app_register. It can only be in th...