1069
SAM9G45 [DATASHEET]
6438K–ATARM–12-Feb-13
obtained (for the positive polarity case, or between (1/256) × VDD and VDD for the negative polarity case). Other
voltage values can be obtained by adding active external circuitry.
For PWM mode, the frequency of the counter can be adjusted to four different values using field PS of
CONTRAST_CTR register.
45.6.3
LCD Interface
Controller supports the following interface configurations: 24-bit TFT single scan, 16-bit STN Dual Scan Mono
(Color), 8-bit STN Dual (Single) Scan Mono (Color), 4-bit single scan Mono (Color).
A 4-bit single scan STN display uses 4 parallel data lines to shift data to successive single horizontal lines one at a
time until the entire frame has been shifted and transferred. The 4 LSB pins of LCD Data Bus (LCDD [3:0]) can be
directly connected to the LCD driver; the 20 MSB pins (LCDD [23:4]) are not used.
An 8-bit single scan STN display uses 8 parallel data lines to shift data to successive single horizontal lines one at
a time until the entire frame has been shifted and transferred. The 8 LSB pins of LCD Data Bus (LCDD [7:0]) can
be directly connected to the LCD driver; the 16 MSB pins (LCDD [23:8]) are not used.
An 8-bit Dual Scan STN display uses two sets of 4 parallel data lines to shift data to successive upper and lower
panel horizontal lines one at a time until the entire frame has been shifted and transferred. The bus LCDD[3:0] is
connected to the upper panel data lines and the bus LCDD[7:4] is connected to the lower panel data lines. The rest
of the LCD Data Bus lines (LCDD[23:8]) are not used.
A 16-bit Dual Scan STN display uses two sets of 8 parallel data lines to shift data to successive upper and lower
panel horizontal lines one at a time until the entire frame has been shifted and transferred. The bus LCDD[7:0] is
connected to the upper panel data lines and the bus LCDD[15:8] is connected to the lower panel data lines. The
rest of the LCD Data Bus lines (LCDD[23:16]) are not used.
STN Mono displays require one bit of image data per pixel. STN Color displays require three bits (Red, Green and
Blue) of image data per pixel, resulting in a horizontal shift register of length three times the number of pixels per
horizontal line. This RGB or Monochrome data is shifted to the LCD driver as consecutive bits via the parallel data
lines.
A TFT single scan display uses up to 24 parallel data lines to shift data to successive horizontal lines one at a time
until the entire frame has been shifted and transferred. The 24 data lines are divided in three bytes that define the
color shade of each color component of each pixel. The LCDD bus is split as LCDD[23:16] for the blue component,
LCDD[15:8] for the green component and LCDD[7:0] for the red component. If the LCD Module has lower color
resolution (fewer bits per color component), only the most significant bits of each component are used.
monochrome and color modes.