Content originally posted in LPCWare by Dave on Thu Sep 27 12:31:12 MST 2012
You are correct...
it's the number of pixels per line, minus 1, for standard TFT...
If you're using a 4 bit mono, then it's pixels/4, minus 1...
If you're using an 8 bit mono, then it's pixels/8, minus 1...
and if you're using an STN, then it's pixels*3/8, minus 1....
Here's an example:
<code>
regValue = 0x00000000; // start out with zero...
// ------------------------------------------------------------------------------------------
// BITS 4:0 Panel Clock Divisor
// Find the dot clock divider with the fastest clock rate to match the requested
// dot clock rate without going over.
// ------------------------------------------------------------------------------------------
for( Divisor=0; Divisor<0x0F; Divisor++ )
{
if( (SystemCoreClock/(Divisor+2)) <= DefaultDisplay.iDotClockHz )
break;
}
regValue |= Divisor; // update value...
// ------------------------------------------------------------------------------------------
// BIT 5 Clock Select - always 0...
// BITS 10:6 AC bias pin frequency - not for TFT displays, so leave 0
// ------------------------------------------------------------------------------------------
// ------------------------------------------------------------------------------------------
// BIT 11 Invert vertical synchronization
// ------------------------------------------------------------------------------------------
if(DefaultDisplay.iInvertVerticalSync)
regValue |= (1<<11);
// ------------------------------------------------------------------------------------------
// BIT 12 Invert horizontal synchronization
// ------------------------------------------------------------------------------------------
if(DefaultDisplay.iInvertHorizontalSync)
regValue |= (1<<12);
// ------------------------------------------------------------------------------------------
// BIT 13 Invert panel clock
// ------------------------------------------------------------------------------------------
if(DefaultDisplay.iInvertPanelClock)
regValue |= (1<<13);
// ------------------------------------------------------------------------------------------
// BIT 14 Invert output enable
// ------------------------------------------------------------------------------------------
if(DefaultDisplay.iInvertOutputEnable)
regValue |= (1<<14);
// ------------------------------------------------------------------------------------------
// BITS 25:16 Clocks per line
// ------------------------------------------------------------------------------------------
switch( DefaultDisplay.iPanelType )
{
case LCD_STANDARD_TFT:
case LCD_ADVANCED_TFT:
case LCD_HIGHLY_REFLECTIVE_TFT:
default:
regValue |= (((DefaultDisplay.iHorizontalPixelsPerLine-1) & 0x3FF) << 16);
break;
case LCD_4BIT_MONO:
regValue |= ((((DefaultDisplay.iHorizontalPixelsPerLine / 4)-1) & 0x3FF) << 16);
break;
case LCD_8BIT_MONO:
regValue |= ((((DefaultDisplay.iHorizontalPixelsPerLine / 8)-1) & 0x3FF) << 16);
break;
case LCD_COLOR_STN:
regValue |= (((((DefaultDisplay.iHorizontalPixelsPerLine * 3)/8)-1) & 0x3FF) << 16);
break;
}
// ------------------------------------------------------------------------------------------
// BIT 26 Bypass pixel clock divider - always 0...
// BITS 31:27 Upper five bits of panel clock divisor - the TFT divisor is never more than 15,
// so these will always be zero...
// ------------------------------------------------------------------------------------------
LPC_LCD->POL = regValue;
</code>
