probe: performance enhancements - Run out of SRAM, it goes quite a lot faster - Cache the DAP clock frequency - Read RDATA and write WDATA all in one go, and merge the turnaround into the ACK phase. Reduces the number of missed PIO SM cycles during an SWD transfer Also fix a compiler warning and demote the loglevel of some debug messages. Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
Picoprobe allows a Pico / RP2040 to be used as USB -> SWD and UART bridge. This means it can be used as a debugger and serial console for another Pico.
Picoprobe documentation can be found in the Pico Getting Started Guide. See “Appendix A: Using Picoprobe”.