General • HM01B0 on Pico2W

Hello

I'm attempting to use this library with my Pico2W: https://github.com/ArmDeveloperEcosyste ... -for-pico/

I haven't been able to get either of the examples working, and I'm not sure why.

What I see:

When I run the terminal example, I see that the program is only reading 0's ($). When I run the usb example, I see the following:

Potential Issues:

The datasheet for the RP2350 mentions several differences between the two chips, for instance:

The four most-significant bits of TRANS_COUNT (CH0_TRANS_COUNT) are redefined as the MODE field, which defines what happens when TRANS_COUNT reaches zero:
◦ This backward-incompatible change reduces the maximum transfers in one sequence from 2^32-1 to 2^28-1.
◦ Mode 0x0 has the same behavior as RP2040, so there is no need to modify software that performs less than
256 million transfers at a time.

but as far as I can tell we should only be transferring 160*120*8 bits at time. I'm not familiar with DMA or PIO so I'm not sure if this breaking change is even relevant.

This PIO change could be relevant as well:

Reduced DMA request (DREQ) latency by one cycle vs RP2040.

but I'm not sure.

The last issue I noticed is that the datasheet for the HM01B0 has the following:
So is this simply a case of me supplying too much voltage? I have it wired to the 3.3V on my board, but In this example, they wire it to the 3.3V pin on the pico with no issue: https://www.raspberrypi.com/news/real-t ... y-pi-pico/

I'd love any pointers, I'm pretty new to the world of microcontrollers so any help is appreciated!

Statistics: Posted by jace1427 — Fri Feb 07, 2025 10:20 pm — Replies 0 — Views 21

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