LCD Registers
1410
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
LCD Controller
Table 20-19. LCDRASTRCTL Register Field Descriptions (continued)
Bit
Field
Type
Reset
Description
24
FRMBUFSZ
R/W
0x0
Frame buffer select.
This mode is valid when LCDTFT is 0 and there are 16 bpp raw data
frame buffers (bpp= 00)
Only for this case, this bit selects whether the frame buffer format is
16 bpp 565 or 12bpp.
The Grayscaler can only take 12 bits per pixel. The frame buffer data
is 16 bits per pixel 565 when FRMBUFSZ is set to 1 and only the 4
most significant bits of each color component are sent to the
Grayscaler input.
0x0 = Framebuffer is 12 bpp packed in bits [11:0]
0x1 = Framebuffer is 16 bpp 565
23
TFTMAP
R/W
0x0
TFT mode alternate signal mapping for palettized framebuffer.
This bit must be 0 for all 12-, 16-, or 24-bpp raw data formats. This
bit must be 1 for 1-, 2-, 4-, or 8-bpp palette lookup data. Valid only in
active matrix mode when LCDTFT = 1.
0x0 = 4 bits per component output data for 1-, 2-, 4-, and 8-bpp
modes are right aligned on LCDDATA[11:0]
0x1 = 4 bits per component output data for 1-, 2-, 4-, and 8-bpp
modes are converted to 5,6,5, format and use LCDDATA[15:0] = {R3
R2 R1 R0 R3 G3 G2 G1 G0 G3 G2 B3 B2 B1 B0 B3}
22
NIBMODE
R/W
0x0
Nibble mode. This bit is used to determine palette indexing and is
used in conjunction with RDORDER.
0x0 = Nibble mode is disabled
0x1 = Nibble mode is enabled
21-20
PALMODE
R/W
0x0
Pallette loading mode. For raw data (12, 16, or 24 bpp) frame
buffers, no palette lookup is employed. Thus, these frame buffers
use the data-only loading mode.
0x0 = Palette and data loading, reset value
0x1 = Palette loading only
0x2 = Data loading only
19-12
REQDLY
R/W
0x0
Palette loading delay.
This 8-bit parameter pauses reading of the Palette data from the
asynchronous FIFO between each burst of 16 words. The delay is in
terms of system clock (SYSCLK) cycles. The value (0-255) used to
specify the number of system clock cycles that should be paused
between bursts of 16 word reads from the asynchronous FIFO while
loading the Palette SRAM. Programming REQDLY = 0x00 disables
this pause when loading the Palette table.
When loading the Palette from system memory, palette data is burst
into the internal Palette SRAM from the Asynchronous FIFO. 1, 2,
and 4-bit per pixel frame buffer encodings use a fixed 16-word entry
palette residing above the video data.
The 8-bit per pixel frame buffer encoding uses a 256-word entry
palette residing above the video data. Likewise, 12, 16, and 24-bit
per pixel frame buffer encodings also define a 256-word entry palette
even though these encodings will not do a full bit-depth palette
lookup. However, the 256-word palette entry must still be read from
DDR as a frame buffer is fetched.
Bursting in 256 words in sequential SYSCLK cycles may cause the
asynchronous FIFO to underflow depending on the DDR burst
bandwidth.
11-10
RESERVED
R
0x0
9
MONO8B
R/W
0x0
Mono 8-bit.
This bit is ignored in all other modes.
0x0 = lcd_pixel_o[3:0] is used to output four pixel values to the panel
each pixel clock transition
0x1 = lcd_pixel_o[7:0] is used to output eight pixel values to the
panel each pixel clock transition.