Owner manual

AN269
AN269REV1 31
6.2.3 Vertical Alignment Signals
The vertical timing alignment signals are easily determined by looking at Figure 17.
The total number of lines is equal to the vertical resolution (notice there are no “blank” lines):
VLinesTotal = (vertical resolution) - 1
The VCSYNC signal becomes active when the vertical line counter is VLinesTotal and becomes inactive
when it is VLinesTotal-1. Therefore:
VSyncStart = VLinesTotal
VSyncStop = VLinesTotal - 1
t
VCSYNC
VCSYNC
HSYNC
Single Video Frame
SPCLK
First Line
Vertical Line
Counter Value
Count = VLinesTotal
Count = VLinesTotal - 1
Count = VLinesTotal - 2
Count =0
Count = VLinesTotal
Figure 17. Frame Type 1 Display Vertical Timing