Help w/ build system on examples/system/ulp_riscv/gpio

[spacewrench]

I'm using esp-idf (origin/master) on Linux and have been able to compile & run many of the examples. However, I can't get the ULP + GPIO example to build correctly. The problem is difficult to trace through the build system...if anyone has figured this out, could you let me know what you did?

I tracked one problem down to errors in the build.make file created for the ULP main.c file -- it tries to execute cmake -E echo, but there is no echo subdirectory to build in. I commented out those lines in the makefile and was able to build a binary, but it won't load on my ESP32 rev1 dev board -- it says the binary is for ESP32S2.

Is the ULP a feature of the S2 devices only? Is there a ULP on my ESP32 rev1?

[ESP_Sprite]

There's two kinds of ULP - one is the older one that has a custom ISA, the other one is newer and is RiscV based. The ESP32 only supports the older one, the -S2 supports both kinds (and in the future, we'll be likely moving to RiscV-only ULP support for newer chips). As the name of the example directory implies, the 'ulp_riscv' examples are only for the newer ULP style, and as such won't run on your ESP32.

[spacewrench]

Understood, thanks!