Search found 133 matches

by meowsqueak
Wed May 22, 2019 12:28 am
Forum: ESP32 IDF
Topic: I2C block transaction limitation - 255 bytes max?
Replies: 1
Views: 111

Re: I2C block transaction limitation - 255 bytes max?

Ok, never mind, turns out I was passing a uint8_t as the length parameter. Embarrassing.

Sorry for the noise. ESP-IDF happily reads (much) more than 255 bytes per I2C transaction. If you read this far, I apologise for wasting your time.
by meowsqueak
Tue May 21, 2019 11:59 pm
Forum: ESP32 IDF
Topic: I2C block transaction limitation - 255 bytes max?
Replies: 1
Views: 111

I2C block transaction limitation - 255 bytes max?

I'm reading blocks of data from an IC device's internal FIFO over I2C. The device implements special FIFO read registers that "loop around" so that the master can continue to read over and over, allowing large amounts of data to be read in a single I2C transaction. I'm having a problem with IDF v3.2...
by meowsqueak
Tue May 21, 2019 9:22 pm
Forum: ESP32 IDF
Topic: Reading from SPI Accelerometer and networking out data at 2000hz
Replies: 11
Views: 624

Re: Reading from SPI Accelerometer and networking out data at 2000hz

Greg Corson wrote:
Tue May 21, 2019 5:17 pm
What I ended up doing ...
Thanks for the summary - very interesting. Some of the breakouts I'm using don't provide easy access to the interrupt pins, but that can be worked around. Does that mean you aren't using the FIFO modes at all?
by meowsqueak
Tue May 21, 2019 9:19 pm
Forum: ESP32 IDF
Topic: Reading from SPI Accelerometer and networking out data at 2000hz
Replies: 11
Views: 624

Re: Reading from SPI Accelerometer and networking out data at 2000hz

assuming I could read that in a single I2C transaction Incidentally, I can't - the chain of I2C instructions (using the IDF driver) runs out of heap space somewhere between trying to read 30 and 60 bytes in a single transaction (malloc fails). EDIT: probably my own stupid fault for using i2c_master...
by meowsqueak
Tue May 21, 2019 2:07 am
Forum: ESP32 IDF
Topic: Reading from SPI Accelerometer and networking out data at 2000hz
Replies: 11
Views: 624

Re: Reading from SPI Accelerometer and networking out data at 2000hz

However, as far as I remember, esp_timer callbacks are serialized, so you a. don't want to spend too much time doing what you need to do there and b. you can expect a bit more jitter in the callback at times. Thanks for your advise so far. What would be "too much time"? For example, let's say I wan...
by meowsqueak
Tue May 21, 2019 1:43 am
Forum: ESP32 IDF
Topic: Reading from SPI Accelerometer and networking out data at 2000hz
Replies: 11
Views: 624

Re: Reading from SPI Accelerometer and networking out data at 2000hz

Specifically with a device with a FIFO, I've used a timer interrupt to wake a task using a semaphore to read out the device succesfully before. Nowadays, you could probably also use an esp_timer callback. That's roughly what I was thinking - have the device automatically fill the FIFO at the config...
by meowsqueak
Mon May 20, 2019 11:30 pm
Forum: ESP32 IDF
Topic: Reading from SPI Accelerometer and networking out data at 2000hz
Replies: 11
Views: 624

Re: Reading from SPI Accelerometer and networking out data at 2000hz

This is part of an imu test rig so it needs to work with a variety of imu. This rig needs to sample several imu at once so they can be compared Regardless, even fifos generate an interrupt and then need to be read on a fairly regular schedule (when the sample rate is 2k) so I’m wondering if the rea...
by meowsqueak
Mon Apr 15, 2019 11:30 pm
Forum: Showcase
Topic: JTAG Debugger that fits most ESP32 Projects
Replies: 12
Views: 4022

Re: JTAG Debugger that fits most ESP32 Projects

I'm curious though - what do you consider "too expensive"? I have a C232HM that works well with the ESP32, and they are US$26 (ex. shipping) each This cable has no level shifting but you are right in principle it works but not as reliable as a debug adapter with level shifting to the used ESP32 sup...
by meowsqueak
Wed Mar 20, 2019 8:23 pm
Forum: ESP32 IDF
Topic: Potential serious issue with MQTT library in ESP-IDF 3.2 - resolved by Espressif?
Replies: 2
Views: 717

Re: Potential serious issue with MQTT library in ESP-IDF 3.2 - resolved by Espressif?

Thank you very much for the detailed reply. I look forward to using this library in 3.2.
by meowsqueak
Tue Mar 19, 2019 9:23 pm
Forum: ESP32 IDF
Topic: Potential serious issue with MQTT library in ESP-IDF 3.2 - resolved by Espressif?
Replies: 2
Views: 717

Potential serious issue with MQTT library in ESP-IDF 3.2 - resolved by Espressif?

In the thread ESP-IDF V3.2-beta3 has been released I see "Integrated esp-mqtt MQTT client library into ESP-IDF". This is good progress - the IDF could do with an official MQTT client - but I'm very concerned about this outstanding issue in that particular library: https://github.com/espressif/esp-mq...

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