ESP32 Forum

Hi,

as the title says, I would like to connect the ESP32 to a 32 bit parallel bus.
I was wondering if it would be possible to use 4 8-bit serial-to-parallel shift registers and connect them using QSPI such that each 8-bit register is connected to its own QSPI data signal. This will of course only work if the QSPI command, address, etc phases can be circumvented/abused for this purpose.

I am working on I2S, it is easy in ESP32 idf <3.0.

But, getting > IDF 4, is another story.

To answer my own question:
After some tests I did, it seems that QSPI can be used to interface to a 32-bit bus by using 4 8-bit shift registers (with parallel outputs) and connect their serial data inputs to each their own QSPI output - this way, 32 bits can be pushed out using just 8 SPI clock pulses.
This, of course, has to be the case for reading data from a 32-bit bus also, if there's any sanity in the world.