ESP32S3 - ULP RISCV example ds18b20_onewire does not build (IDFGH-7075)

[andrew-elder]

Environment

• Development Kit: ESP32-S3-DevKitM-1
• Module or chip used: ESP32-S3-MINI-1
• IDF version: "master" v5.0-dev-2046-g5963de1caf
• Build System: idf.py
• Compiler version: xtensa-esp32-elf-gcc (crosstool-NG esp-2021r2-patch3) 8.4.0
• Operating System: Linux
• Using an IDE?: No

Problem Description

ESP32S3 ULP compile for RISCV does not work.

I'm trying to get RISCV ULP code to compile and run on an ESP32S3. My own code gave include file errors, so I looped back to try a reference example. I used this example ds18b20_onewire. It compiles correctly for ESP32S2, but not ESP32S3.

Expected Behavior

Compilation without errors for ESP32S3.

Actual Behavior

Observe

/home/logix/projects/krado/sw/ds18b20_onewire/main/ulp/main.c:18:10: fatal error: ulp_riscv/ulp_riscv.h: No such file or directory
 #include "ulp_riscv/ulp_riscv.h"
          ^~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.

Steps to reproduce

Copy the ds18b20_onewire example.

Edit sdkconfig.defaults so that it contains

CONFIG_IDF_TARGET="esp32s3"
# Enable ULP
CONFIG_ESP32S3_ULP_COPROC_ENABLED=y
CONFIG_ESP32S3_ULP_COPROC_RISCV=y
CONFIG_ESP32S3_ULP_COPROC_RESERVE_MEM=4096
# Set log level to Warning to produce clean output
CONFIG_BOOTLOADER_LOG_LEVEL_WARN=y
CONFIG_BOOTLOADER_LOG_LEVEL=2
CONFIG_LOG_DEFAULT_LEVEL_WARN=y
CONFIG_LOG_DEFAULT_LEVEL=2

then

1. idf.py fullclean
2. idf.py set-target esp32s3
3. idf.py build

Observe the compilation error.

[andrew-elder]

And then there is this code in the "gpio" example

if(NOT IDF_TARGET STREQUAL "esp32s2")
    #IDF-4514
    message(FATAL_ERROR "DO NOT BUILD THIS APP FOR ANY TARGET OTHER THAN ESP32-S2 OTHERWISE YOU MAY BRICK YOUR DEVICE")
    return()
endif()

[andrew-elder]

I see https://esp32.com/viewtopic.php?t=21906 that ULP is not supported yet. See related #7963, Any updates on when it will be supported?

[ESP-Marius]

Hi @andrew-elder ,

As you've noticed the ULP examples are currently not supported on S3, even the ULP API is currently disabled (see 2efd009 for context)

There is a fix in review for the bug mentioned above, as soon as that is merged then we'll add S3 support to these examples. If we dont encounter any issues with the proposed fix then I would estimate that we should be able to add support pretty quickly (as in sometime in April)

For reference: you can see which targets an example supports by looking at the table at the top of the examples readme.md.

[andrew-elder]

@ESP-Marius - it's been a couple of months. Any updates?

[wuyuanyi135]

I am also designing a product that requires ulp support. Can I have the estimated release date of the fix?

If I am using the ulp without sleep. Is it safe to bypass the error check and continue to use the feature?

[ESP-Marius]

Sorry for the long wait guys. We've been unable to go back to our office in Shanghai for the last few months due to Covid restrictions, which unfortunately slowed down things a lot. But now we are finally back, and the MR for the above mentioned bug is ready to merge, and an MR for re-enable ULP is under review.

Should be able to get these two merged before the end of the week.

[ESP-Marius]

If I am using the ulp without sleep. Is it safe to bypass the error check and continue to use the feature?

Unfortunately not, as it could damage the chip permanently.

[wuyuanyi135]

@ESP-Marius Very pleased to hear that things are going back to normal and the problem will finally get fixed. Stay safe!