RE: Graphics Overlay

schwiegjc

This subject has been talked about before. I built the overlay graphics card and then used the existing Flight Drone code. The graphics overlay actually worked great. The project needs to read a tilt sensor (at 10Hz) and Parallax GPS Sensor (at 1 Hz) and then display the data with dials over a camera image. I configure a cog for the each sensor (I also give the cog the address of the global variable) to extract the sensor data, and then use the main cog to display the data on the TV output. The problem is data displayed on the screen is very jump. I suspect the main cog is reading the global variables while the other cogs are writing to them. If the read sensor functions are placed in the main cog code, then the display is very stable but the update rate will be 1Hz.

Paul Baker

The best way to combat this is for the driver to indicate when it's in the sync portion of it's drawing, and only update the data when it's in sync. If you are using TV.spin the driver already does this, the first long pointed to by the pointer you hand the start method is the driver status, look at the explanation for tv_status at the end of TV.spin

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Paul Baker