The PIO hardware has some free parameters that may vary between chip products. These should be provided in the chip datasheet, but are also exposed here.
| FIFO_DEPTH | The depth of the state machine TX/RX FIFOs, measured in words. Joining fifos via SHIFTCTRL_FJOIN gives one FIFO with double this depth. |
| SM_COUNT | The number of state machines this PIO instance is equipped with. |
| IMEM_SIZE | The size of the instruction memory, measured in units of one instruction |