ISP via RS232

The pyCPU has a pin (with a pushbutton added to it) which can be used to switch the CPU into Programming Mode.

Then by sending a new programm via RS232 to the CPU  the programm of pyCPU can be updated this program is the ProgIt.py Programm.

Since pyCPU uses SRAM of an FPGA to store the Programcode and the Programdata the new Programm is available only as long as the Powersupply is not switchted of or the FPGA is not reconfigured by the configuration flash, but it is good for fast testing of the pyCPU code without rerunning the Synthesis Programm.