I'm using a video overlay unit (Xbob from Decade Engineering) together with a PIC 16F627,max232 chip & single channel remote gate TX/RX as a simple "on screen egg timer". The remote is just to activate the timer. The PIC is connected to the overlay unit via an rs232 connection and just sends the strings/commands to the unit.
The overlay unit runs on 12V & the PIC on 5V of course. I'm using a SMPS with dual outputs & common ground. The problem is that the PIC hangs up as soon as the overlay unit is swithed on. I have to leave the power switch of the overlay unit in the on position and switch the whole lot on simultaneously from the wall socket to get it working; and sometimes a few times at that. Once it is working, it operates fine for a few hours, & then the PIC hangs again.
Could it be because of the different PSU voltages or because the signal Gnd is the same as the PSU Gnd? I know it is not the remote as it happens when I use a pushbutton too.
The overlay unit runs on 12V & the PIC on 5V of course. I'm using a SMPS with dual outputs & common ground. The problem is that the PIC hangs up as soon as the overlay unit is swithed on. I have to leave the power switch of the overlay unit in the on position and switch the whole lot on simultaneously from the wall socket to get it working; and sometimes a few times at that. Once it is working, it operates fine for a few hours, & then the PIC hangs again.
Could it be because of the different PSU voltages or because the signal Gnd is the same as the PSU Gnd? I know it is not the remote as it happens when I use a pushbutton too.