Design Recipes for FPGAs
162
There are some constraints about the spacing of the data between
pulses which will be considered later in this chapter, but it is clear
that the key to a correct VGA output is the accurate definition of
timing and data by the VHDL.
Basic pixel timing
If there is a space of 25.17 μs to handle all of the required pixels,
then some basic calculations needs to be carried out to make sure
that the Field Programmable Gate Arrays (FPGA) can display the
correct data in the time available. For example, if we have a 640
480 VGA system, then that means that 640 pixels must be sent to
the monitor in 25.17 μs. Doing the simple calculation ...