Awesome

Some excercises for RP2040 and its PIO

• pulses: Two functions to time and send pulse trains at PIO clock precision
• rp2_util: A set of small functions to manage state machines and to use DMA with state machines and UART
• rp2_pio_lcd: A driver for 1602 kind LCD displays based on Dave Hylands LCD package using PIO for I/O.