ESP8266 Community Forum

- Mon Aug 16, 2021 4:59 am #92080 The guys from Espressif are definitely no strangers to typo's . But what makes it interesting is that this function is also (by Espressif) used for other purposes than I2S. It seems to just set the system clock + division parameters. I might have a go sometime to just try some things and see what happens. If only we could monitor what the actual clock frequency is (+ I/O bus too), now I don't see another way than counting cycles of a busy loop against a "wall" clock.

- Mon Aug 16, 2021 7:35 pm #92081

The guys from Espressif are definitely no strangers to typo's . But what makes it interesting is that this function is also (by Espressif) used for other purposes than I2S. It seems to just set the system clock + division parameters. I might have a go sometime to just try some things and see what happens. If only we could monitor what the actual clock frequency is (+ I/O bus too), now I don't see another way than counting cycles of a busy loop against a "wall" clock.

Yeah it seems to be used for SPI, or at least the SLC stuff - the one thing it doesn't seem to ever be used for right now is i2c!!! LOL

I wonder if we can set the divisors to various values, measure the i2s bit clock and deduce it from there?

This may also help out:
http://ratzzo.net/index.php/posts/rom-i2c-readreg-dissection

- Tue Aug 17, 2021 3:14 am #92084 That's interesting, so my huch may be right after all!

- Tue Aug 17, 2021 3:27 am #92085 This one is interesting too: http://cholla.mmto.org/esp8266/bootrom/boot.txt