Raspberry Pi Pico ADC changes the sampling rate in Free-running Sampling mode

[leezisheng]

I am configuring the ADC sampling rate here. Due to unknown reasons, the DIV register cannot be configured here. The actual sampling period is fixed at 65.
Can anyone help me what is going wrong here？

[robert-hh]

The right hand expression div_value | (int_part << 8) | frac_part seems wrong. I would have expected it to be (int_part << 8) | frac_part. The previous int_part of the DIV register is 0xbfff. So if you OR 100 (0x64) to it, it will still stay 0xbfff.

[leezisheng]

And data bits 31:24 are reserved bits, we should not operate on them, so why my original expression does not work properly, but it does after modification.？

[robert-hh]

According to the documentation, the div registers are all initialized to 0.

Yes. That is the case. Therefore I assume that you are working with a different register controlling the DMA transfer rate.

[leezisheng]

According to the documentation, the div registers are all initialized to 0.And data bits 31:24 are reserved bits, we should not operate on them, so why my original expression does not work properly, but it does after modification.？

[leezisheng]

I assume that you are working with a different register controlling the DMA transfer rate.
I don’t quite understand. My DIV register address setting should be correct.

[leezisheng]

I don’t quite understand. My DIV register address setting should be correct.
and Sorry, this is my first time using github issue and I am a little unfamiliar with the operations, such as citation and reference options.

[leezisheng]

And data bits 31:24 are reserved bits, we should not operate on them, so why my original expression does not work properly, but it does after modification.？