Because most are hobbyists who want the easiest, quickest, cheapest, option; no resistors, no level shifters, something which can be wired directly to a 5V system using 5V signalling without having to worry about having done that, not having to do anything beyond connecting wires and supplying power, not having any worries or issues having done so.I've never understood why people find adding two resistors in a voltage divider such a problem. It's only at very high speeds that an active level shifter is needed.
When using a microcontroller module, adding level-shifters or resistor dividers means having a rats-nest of wiring or having to build or use interface boards between that and what they are connecting to. That's extra effort and extra cost, it turns what would have been a simple "just wire it up" project into something else.
It's not that they couldn't do that; it's that they prefer not to, aren't going to, don't have the additional components on hand to do it, or simply don't wish to spend any extra time or money on the hardware of a project. It's extra faff they don't wish to entertain.
Microcontrollers which are truly "5V tolerant" are a godsend in that respect; facilitating nothing more than wire it up, and no worries or issues having done so.
Unfortunately the Pico-range, RP2 devices, boards and modules using those, are "only tolerant of 5V, tolerant of up to 5.5V, when the chip is powered", so it's not so simple as wire it up and no worries or issues having done so; there's that very big issue of what happens if connected to a 5V signal and not powered up.
My recommendation for those wanting to use the RP2 with 5V systems is to deal with that, buy an RP2 board or module which includes level-shifting. One such example is Mitchelectronics RP-Duino and there may be others, use something else, or choose a different adventure.
Statistics: Posted by hippy — Sat Aug 02, 2025 12:38 pm