Line Pulse
(LCD_HSYNC)
Line 0 Data
PPL = 17
Pixel Clock
(LCD_PCLK)
Data
(LCD_D[x:0])
Frame Pulse
(LCD_VSYNC)
IHS = 0
HBP = 1
LcdEN = 1
IVS = 0
VSW = 0
Line 1 Data
Line 2 Data
HFP = 1
HSW = 6
VFP = 2
Registers
1069
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Liquid Crystal Display Controller (LCDC)
23.3.10.4
Vertical Back Porch (VBP)
NOTE:
The line clock transitions during the generation of the VBP line clock wait periods. Note also
that you must adjust the value of VBP appropriately such that enough line clock cycles are
permitted to elapse; this allows the palette to be completely filled via the DMA, and allows a
sufficient number of encoded pixel values to be input from the frame buffer, processed by the
dither logic, then placed in the output FIFO, ready to be output to the LCD data lines.
The 8-bit vertical back porch (VBP) field is used to specify the number of line clocks (or LCD_HSYNC) to
insert at the beginning of each frame. The VBP count starts just after the LCD_VSYNC signal for the
previous frame has been negated for active mode, or the extra line clocks have been inserted as specified
by the VSW bit-field in passive mode. After this has occurred, the value in VBP is used to count the
number of line clock periods to insert before starting to output pixels in the next frame. VBP generates
from 0–255 extra line clock cycles (see
).
Figure 23-34. Vertical Back Porch (VBP)