![Texas Instruments AM1808 Скачать руководство пользователя страница 1064](http://html.mh-extra.com/html/texas-instruments/am1808/am1808_technical-reference-manual_10945581064.webp)
Registers
1064
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Liquid Crystal Display Controller (LCDC)
23.3.9 LCD Raster Timing Register 0 (RASTER_TIMING_0)
The LCD raster timing 0 register (RASTER_TIMING_0) contains four bit-fields that are used as modulus
values for a collection of down counters, each of which performs a different function to control the timing
of several of the LCD’s pins. The RASTER_TIMING_0 is shown in
and described in
.
Figure 23-30. LCD Raster Timing Register 0 (RASTER_TIMING_0)
31
24
23
16
HBP
HFP
R/W-0
R/W-0
15
10
9
4
3
0
HSW
PPL
Reserved
R/W-0
R/W-0
R-0
LEGEND: R = Read only; -
n
= value after reset
Table 23-20. LCD Raster Timing Register 0 (RASTER_TIMING_0) Field Descriptions
Bit
Field
Value
Description
31-24
HBP
0-FFh
Horizontal Back Porch. Encoded value (HBP + 1) is used to specify number of LCD_PCLKs to add to
the beginning of a line transmission before the first set of pixels is output to the display (program to
value minus one). Note that pixel clock is held in its inactive state during the beginning of line wait
period in STN mode while it is active in TFT mode.
23-16
HFP
0-FFh
Horizontal Front Porch. Encoded value (HFP + 1) is used to specify number of LCD_PCLKs to add to
the end of a line transmission before line clock is asserted (program to value minus one). Note that pixel
clock is held in its inactive state during the end of line wait period in STN mode while it is active in TFT
mode.
15-10
HSW
0-3Fh
Horizontal Sync Pulse Width. Encoded value (HSW + 1) is used to specify number of LCD_PCLKs to
pulse the line clock at the end of each line (program to value minus one). Note that pixel clock is held in
its inactive state during the generation of the line clock in STN mode while it is active in TFT mode.
9-4
PPL
0-3Fh
Pixels per Line. This value specifies the number of pixel transmissions per line . Number of pixels per
Line = (PPL + 1) × 16
3-0
Reserved
0
Reserved
23.3.9.1
Pixels-Per-Line (PPL)
NOTE:
PPL must be programmed to the value required minus 1 (for example, for a 640-pixel-per-
line LCD panel, PPL = (640/16) - 1 = 40 - 1 = 39 = 27h).
The pixels-per-line (PPL) bit-field is used to specify the number of pixels in each line on the screen. The
number of pixels per line = (PPL + 1) × 16, represents the screen width. PPL is a 6-bit value. Taking into
account that the bottom 4 bits of this register are reserved, it is possible to support displays where the
number of pixels-per-line ranges from 16-1024. PPL is used to count the correct number of pixel clocks
that must occur before the line clock can be pulsed.