Some key specs:
- SoC:
- name: RP2040. Custom designed by Raspberry Pi Foundation, likely the first they make themselves rather than using a Broadcom chip. But the design still is closed source, likely wouldn't be easy to open source due to the usage of closed proprietary IP like the ARM
 - dual core ARM Cortex-M0+
 - frequency: 2 kHz to 133 MHz, 125 MHz by default
 - memory: 264KB on-chip SRAM
 
 - GPIO voltage: 3.3V
 
Ciro Santilli