Cirrus-logic AN269 Manual de usuario descargar pdf (Pagina 61)

AN269

AN269REV1 61

Next, the Horizontal Synchronization Signals can be determined, using the following equations:

HClkTotal = tHORIZ - 1

HClkTotal = 90 - 1 = 89 (SPCLK periods)

Therefore:

HSyncStart = HClkTotal

HSyncStart = 89

HSyncStop = HClkTotal - tHSYNC

HSyncStop = 89 - 1 = 88

HBlankStart = HClkTotal - tHSYNC - tHFRONTPORCH - 1= 89 - 1 - 2 - 1 = 85

HBlankStop = HClkTotal - tHSYNC - tHFRONTPORCH - tActive - 1 = 89 - 1 - 2 - 80 - 1= 5

HActiveStart = HBlankStart = 85

HActiveStop = HBlankStop = 5

HClkStart = HClkTotal - tHSYNC - tHFRONTPORCH - 6 = 89 - 1 - 2 - 6 = 80

HClkStop = HClkTotal - tHSYNC - tHFRONTPORCH - tActive - 1 = 89 - 1 - 2 - 80 - 6 = 0

Now, the vertical timing register settings can be determined. Using the equations from "Vertical Alignment Signals",

the following values are obtained:

VLinesTotal = Tvert

VLinesTotal = 240

VSyncStart = VLinesTotal -1 = 239

VSyncStop = VSyncStart -1 = 238

VBlankStart = 0

VBlankStop = 0

VActiveStart =239

VActiveStop =240

Again, we can set VClkStart and VClkStop to VLinesTotal:

VClkStart = VClkStop = VLinesTotal = 240

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Cirrus-logic AN269 Manual de usuario Pagina 61