The problem itself is not exactly documented, but it's somewhat implied by the facts in the datasheet: see for example 2.12.4. The RP2040 itself will start running soon after the power rail reaches about 1V, but that's not enough for the CPU to run reliably, nor for the flash and/or the boot button detect to work. So unless the 3.3V supply ramps fairly quickly from 1V to 3.3V then the RP2040 will crash.
The usual solution is to have an external power-good detect circuit feeding the RP2040 reset (the 'RUN' pin). This can usually be achieved with a transistor and a couple of passive components, or there are dedicated power-on-reset/supply monitor/watchdog chips that might be a better choice for your application - small and low power consumption, and not particularly expensive.
The usual solution is to have an external power-good detect circuit feeding the RP2040 reset (the 'RUN' pin). This can usually be achieved with a transistor and a couple of passive components, or there are dedicated power-on-reset/supply monitor/watchdog chips that might be a better choice for your application - small and low power consumption, and not particularly expensive.
Statistics: Posted by arg001 — Fri Apr 19, 2024 9:26 pm