ESP32-S3 wake on UART edge threshold off by 1 (IDFGH-11451)

[xyzzy42]

Answers checklist.

• I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

IDF version.

v5.3-dev-277-gc8243465e4

Espressif SoC revision.

ESP32-S3 revision v0.2

Operating System used.

Linux

How did you build your project?

Command line with idf.py

If you are using Windows, please specify command line type.

None

Development Kit.

ESP32-S3 DevkitC

Power Supply used.

USB

What is the expected behavior?

When uart_set_wakeup_threshold(EXAMPLE_UART_NUM, 3) is called the UART should wake the device from lightsleep after 3 edges. This is in the light_sleep example program.

What is the actual behavior?

It takes 4 edges to wake from light sleep.

Example given in documentation is 'a' has 3 edges. However 'a' does not wake the UART. It takes two 'a' to wake.

Another test, 'e', which has four edges (0 10100110 1), does with with a single 'e'.

I also tried sending binary 0 byte. This has one edge. It takes four to wake.

If I set set the threshold higher, for example to 4, then it takes 5 zero bytes to wake.

It seems value is off by one and takes one additional edge to wake than it should.

Note that the test script for light_sleep sends 'U' with 8 edges, so it will not fail even if the threshold is off by one.

Steps to reproduce.

1. Run light_sleep example.
2. Attempt to wake with single 'a' character, which should wake.
3. Does not wake on UART.
4. Sending additional 'a' character will wake.

Debug Logs.

No response

More Information.

No response