They are using buffers (good so far), it's just how they drive the buffers as open collectors, when are not really open-collectors ... fast switching from output 0 to high-impedance input. And they got stuck outputting 1 instead of 0 (or something like that), because of too high pull-down resistor between the buffer and RP2350.Won't this affect the bus pirates functionality at least partially? The description sounds like while it's primary use is to talk to other chips with whatever interface you want it can also sniff buses like SPI and I2C. That would be the point where the strong pull-downs could interfere. But for normal chip to chip communication this should not be a big issue.
That's a shortcut. I used something like that, (SAE J1850 PWM. + ATmega) as a hack, as a last resort, it works sometimes, but it's definitely not advisable. I wouldn't put such contraption in a finished product.
All the fuss around a sloppy design and rushed release, but hey, it has flying colors.The PCB was revised so the button uses the pull-up and connects to ground, but we also rely heavily on the pull-downs when doing open collector bus types.
The pull-down holds the IO pin low behind the buffer, so the PIO can just manipulate the buffer direction without also managing the GPIO direction.
Statistics: Posted by gmx — Fri Sep 13, 2024 1:25 am