Planar LC1200R user manual Timing and Frequency, Video, Horizontal and Vertical Sync

4.4Timing and Frequency

4.4.1Video, Horizontal and Vertical Sync

Figure 6 illustrate video timing relationships the LC1200R operates within when the specified video mode (Table 5 Video Mode Definitions) is applied.

Front Porch defines the time from end of active video data to the start of Horiz/Vert Sync Pulse.

Back Porch defines the time from end of Horiz/Vert Sync Pulse to the start of active video data.

Blanking is the total time comprising Front Porch, Back Porch and Sync Pulse time(s).

The horizontal sync circuitry synchronizes to horizontal frequencies of 31.468 KHz ±0.5 KHz, 48.077KHz ±0.5KHz, and 56.476KHz ±0.5KHz. Horizontal sync pulse width variation is 1.813- µsec to 3.813-µsec. The LC1200R will "sync" to the specified format vertical frequencies between 60Hz and 72Hz without adjustment.

Absence of Horizontal and/or Vertical Sync will not damage the LC1200R.

4.5Video Signal On-Off Sequences

The sequence for bringing up and removal of each video input signal can be in any sequence or combination of input signals.

Table 6. Video Mode Timing Data
		Video Modes
		IBM VGA		VESA
	Resolution	640x400	640x480	800x600	1024x768
	Video Clock	25.175 MHz	25.175 MHz	50.000 MHz	75.000 MHz
	Horizontal Scan
	Freq.	31.468 KHz	31.468 KHz	48.077 KHz	56.476 KHz
	Horizontal Line	31.778 us 800	31.778 us 800	20.800 us 1040	17.707 us 1328
	Period	pixels	pixels	pixels	pixels
	Horizontal	6.356 us 160	6.356 us 160	4.800 us 240	4.053 um 304
	Blanking	pixels	pixels	pixels	pixels
	Horizontal Sync			2.400 us 120	1.813 us 136
	Pulse	3.813 us 96 pixels	3.813 us 96 pixels	pixels	pixels
	Horizontal Front
	Porch	0.636 us 16 pixels	0.636 us 16 pixels	1.120 us 56 pixels	0.320 us 24 pixels
	Horizontal Back				1.920 us 144
	Porch	1.907 us 48 pixels	1.907 us 48 pixels	1.280 us 64 pixels	pixels
	Horizontal Active	25.422 us 640	25.422 us 640	16.000 us 800	13.653 us 1024
	Display	pixels	pixels	pixels	pixels
	Horizontal Sync
	Polarity	-	-	-	-
	Vertical Scan Freq.	70.087 Hz	59.94 Hz	72.184 Hz	70.069
	Vertical Frame	14.268 ms 449	16.683ms 525	13.853 ms 666	14.272 ms 806
	Period	lines	lines	lines	lines
	Vertical Blanking	1.557 ms 49 line	1.430 ms 45 line	1.373 ms 66 lines	0.673 ms 38 lines
	Vertical Sync	0.064 ms 2 lines	0.064 ms 2 lines	0.125 ms 6 lines	0.106 ms 6 lines

LC1200R User’s Guide 021-0183-00 Rev A 15 of 29