Search found 4 matches

by moondew
Mon Nov 27, 2017 8:14 pm
Forum: ESP-IDF
Topic: Floating the Flash SPI pins to allow a 2nd processor to access flash memory
Replies: 6
Views: 6705

Re: Floating the Flash SPI pins to allow a 2nd processor to access flash memory

Unfortunately, holding the ESP32 in reset does not allow access to the flash memory from a second processor.

It looks like we will have to add a second flash memory part on one of the application SPI controller. Not a big deal except for the time and expense of turning the board.
by moondew
Fri Nov 24, 2017 6:24 pm
Forum: ESP-IDF
Topic: Floating the Flash SPI pins to allow a 2nd processor to access flash memory
Replies: 6
Views: 6705

Re: Floating the Flash SPI pins to allow a 2nd processor to access flash memory

Except once all the interrupts and caching has been disabled, it is not possible to display debugging output.

At this point we are looking at simply having the second processor directly hold the ESP32 in reset while it is reading the flash.
by moondew
Wed Nov 22, 2017 3:20 pm
Forum: ESP-IDF
Topic: Floating the Flash SPI pins to allow a 2nd processor to access flash memory
Replies: 6
Views: 6705

Re: Floating the Flash SPI pins to allow a 2nd processor to access flash memory

Note that first we call disable_interrupts_caches_and_other_cpu().

At the end we // loop here waiting for a specific gpio pin to change state, then reboot.

These two things work fine, it is just that the SPI bus is still driven.
by moondew
Mon Nov 20, 2017 8:18 pm
Forum: ESP-IDF
Topic: Floating the Flash SPI pins to allow a 2nd processor to access flash memory
Replies: 6
Views: 6705

Floating the Flash SPI pins to allow a 2nd processor to access flash memory

Hi, We have a board were we need to force the ESP32 to float it's SPI pins to the flash memory to allow a second processor to read. Once it has been read the ESP32 reboots. It seems simple enough, but have so far been unsuccessful. It appears the ESP32 is still driving the SPI output pins. The secon...