Gotcha, seems a bug snuck into esp-idf when we added the backtrace code. Quick fix: open components/esp32/cpu_util.c and add near the other includes. We'll also fix this in the main esp-idf branch.

To get into download mode, GPIO0 should be pulled down and EN (=reset) should be pulsed low to reset the chip. In theory, if you have any devboard worth its salt, esptool.py should do that using the hardware handshake lines that are connected to gpio0 and EN. You can do it manually as well if you th...

That basically means something has gone wrong communicating with the ESP32. What hardware do you use, as in, what kind of dev board? Maybe you have another program, eg Minicom, which also has opened the serial port running at the same time?

Yes, you should; up to 16MB should work just fine. What is the trouble you're running into?

Strange. Have you enabled the "Make exception and panic handlers JTAG/OCD aware" option? That should make the esp32 halt where the exception happened instead of panic'ing. Edit: I've heard that other people also get this behaviour, even with the option I mentioned enabled. Will look into this, maybe...

We're still working on it. The reference design includes PoE as well, but the engineers are having some trouble bringing that up. As soon as we have a working and tested design, I'll see if I can post the schematics.

Small nitpick: The ROM isn't entirely unused when the application is booted. There are some useful C functions located in ROM; esp-idf links to them if possible because executing them is very fast and does not put pressure on the flash cache. For example, if you select nano-printf, that is entirely ...

Yes, you can. Basically, call portDISABLE_INTERRUPTS (and portENABLE_INTERRUPTS after you're done) and the interrupts on that core should stop firing, stopping task switches as well. Be aware that dependent on what you do, instructions may still not execute at the same speed because of e.g. bus cont...

It should be merged pretty soon now, I hope before the weekend.

The SPI driver will actually be fully capable of interrupt-driven DMA transfers. You basically feed it the transfers you want it to do using a queue and it will give you back the transfers it finished using another queue.