Building a Standards Converter

[ppppenguin]

I cobbled together a bit banger for the  FPGA  but there was no activity at all from it, after a bit of head scratching I found the reason. The only clock source I have is the 27/ 13.5  MHz from the Video decoder but inconveniently at start up, by default there is no clock output,  it has to be switched on by the I2c bus.

Sawing off the branch you're sitting on I've got something a bit like that in one of my designs. I have to provide a temprary clock to the control logic during startup until the correct clock is available and the software in the microcontroller operates a changeover switch int he FPGA. It would be entirely possible for the software to sabotage the FPGA to the point of it needing a reboot.

Well done for getting the 5:4 working.