Search found 22 matches

by aschweiz
Tue Feb 28, 2017 7:59 am
Forum: Report Bugs
Topic: Unable to add more than 1 characteristic to a service
Replies: 4
Views: 1150

Re: Unable to add more than 1 characteristic to a service

It was the last parameter in esp_ble_gatts_create_service:

Code: Select all

esp_ble_gatts_create_service(gl_test.gatt_if, &gl_test.service_id, 1 + (nofCharacteristics() * 3));


But I've since switched to the new "database"-based API where you don't have the number of characteristics any more.
by aschweiz
Fri Feb 03, 2017 1:38 pm
Forum: Report Bugs
Topic: NVS crashing ESP32 after used a few times
Replies: 8
Views: 1697

Re: NVS crashing ESP32 after used a few times

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 ...
by aschweiz
Thu Feb 02, 2017 3:00 pm
Forum: Report Bugs
Topic: Aborting an OTA update
Replies: 1
Views: 456

Aborting an OTA update

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 ...
by aschweiz
Mon Jan 30, 2017 7:59 pm
Forum: ESP32 HDK
Topic: Question on antenna matching
Replies: 3
Views: 1012

Re: Question on antenna matching

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
by aschweiz
Mon Jan 30, 2017 7:47 pm
Forum: ESP32 HDK
Topic: Question on antenna matching
Replies: 3
Views: 1012

Re: Question on antenna matching

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 ...
by aschweiz
Fri Jan 27, 2017 5:52 pm
Forum: ESP32 HDK
Topic: Question on antenna matching
Replies: 3
Views: 1012

Question on antenna matching

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 ...
by aschweiz
Thu Jan 19, 2017 10:40 am
Forum: Report Bugs
Topic: Potential timing issue in wifi stack or mbedtls?
Replies: 0
Views: 294

Potential timing issue in wifi stack or mbedtls?

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...
by aschweiz
Sat Jan 07, 2017 1:19 pm
Forum: Report Bugs
Topic: Unexpectedly low floating-point performance in C
Replies: 15
Views: 4668

Re: Unexpectedly low floating-point performance in C

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 ...
by aschweiz
Sat Jan 07, 2017 12:59 pm
Forum: Report Bugs
Topic: Unexpectedly low floating-point performance in C
Replies: 15
Views: 4668

Re: Unexpectedly low floating-point performance in C

Hi Angus,

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

cheers
Andreas
by aschweiz
Fri Jan 06, 2017 9:37 am
Forum: ESP32 SDK
Topic: Bluetooth LE API questions: esp_ble_gatts_app_register
Replies: 2
Views: 668

Re: Bluetooth LE API questions: esp_ble_gatts_app_register

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 onl...