Search found 15 matches

by this.wiederkehr
Thu Sep 09, 2021 3:24 pm
Forum: General Discussion
Topic: himem page change delays isr
Replies: 4
Views: 2458

Re: himem page change delays isr

To give a rough estimate. the delay due to cache reload is about 3 to 4 ms. Is that expected?
by this.wiederkehr
Thu Sep 09, 2021 10:24 am
Forum: General Discussion
Topic: himem page change delays isr
Replies: 4
Views: 2458

Re: himem page change delays isr

@ESP_Sprite Thank you for your answer with the explanation about the cache being flushed. I indeed think that this is actually impacting my isr. Any chance, that I can change my isr in such a way that there is no impacted by the cache having been flushed? Did I understand correctly, that when placin...
by this.wiederkehr
Thu Sep 09, 2021 7:05 am
Forum: General Discussion
Topic: himem page change delays isr
Replies: 4
Views: 2458

himem page change delays isr

I just observed, that when changing the page in the himem api with esp_himem_unmap and esp_himem_map these two calls influence the timing of an isr which is triggered by a pin level change. What is going on here? Actually I'd like to understand what is going on and probably someone can shed some mor...
by this.wiederkehr
Fri Feb 12, 2021 9:25 am
Forum: General Discussion
Topic: How do you setup a UART Rx interrupt on a ESP32-S2?
Replies: 5
Views: 12861

Re: How do you setup a UART Rx interrupt on a ESP32-S2?

Having spent a night fithing with this. Here is the key:
You can not directly access the UART0.fifo.rw_byte on esp32s2 but have to use READ_PERI_REG(UART_FIFO_AHB_REG(0))

Hope this helps
by this.wiederkehr
Tue Jan 12, 2021 12:06 am
Forum: General Discussion
Topic: RFC: ESP32_WIFI_CACHE_TX_BUFFER_NUM
Replies: 0
Views: 1756

RFC: ESP32_WIFI_CACHE_TX_BUFFER_NUM

This got introduced here and I do not understand the behaviour: https://github.com/espressif/esp-idf/commit/368d623e1af2a43a08a5ec1b5983a75b70ca4071 If SPIRAM is available but not for use by malloc this change will make internal ram very tight. So, I tried to manually setting the number of caches to...
by this.wiederkehr
Mon Nov 02, 2020 3:51 pm
Forum: General Discussion
Topic: gettimeofday from isr crashes
Replies: 3
Views: 4423

Re: gettimeofday from isr crashes

hey mikemoy well, I don't care if the answers I am getting are rude or not as long as it helps me to get forward... So, let me rephrase the question as I don't see how the example you linked would help me: The original question I have: How can I get the exact timeofday of a pin (gpio interrupt) chan...
by this.wiederkehr
Tue Oct 27, 2020 6:30 pm
Forum: General Discussion
Topic: gettimeofday from isr crashes
Replies: 3
Views: 4423

Re: gettimeofday from isr crashes

Well this is quite an old question. But I still could not figure out how to do this in a nontrivial way. I do use the timer to get a timestamp in the isr and assemble the time later by using the timer and gettimeofday function. By subtracting the difference in the timer value from the gettimeofday I...
by this.wiederkehr
Wed Aug 26, 2020 6:07 am
Forum: General Discussion
Topic: Time sync over wifi
Replies: 1
Views: 2865

Re: Time sync over wifi

Just in case somebody is visiting this:

since a few days there is a new function in the wlan api (only esp-idf 4.2 ):

esp_wifi_get_tsf_time

which seems to be made for the task at hand.
by this.wiederkehr
Sat Jul 04, 2020 1:29 pm
Forum: General Discussion
Topic: Time sync over wifi
Replies: 1
Views: 2865

Time sync over wifi

I have multiple esp32 which are connected over wlan with an ap also running on a esp32. I'd like to sync their clock to an accuracy of about 1ms. There are multiple things which I could imagine that would work: * use wlan beacons The question here is if there is access to the beacon event or if this...
by this.wiederkehr
Fri May 29, 2020 3:26 pm
Forum: General Discussion
Topic: gettimeofday from isr crashes
Replies: 3
Views: 4423

gettimeofday from isr crashes

How to get the timeofday from an isr? If I do use gettimeofday from isr it crashes if the application is also executing gettimeofday because the lock is acquired already by the application. Here is the relevant traceback: 0x40097ba0: invoke_abort at panic.c:? 0x40097f11: abort at ??:? 0x4008685b: lo...