at91sam9263 ATMEL Corporation, at91sam9263 Datasheet - Page 880

• Manufacturer Part Number: at91sam9263
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

output brings the value of the polarity (POL) bit in the PWM control register: CONTRAST_CTR.
Otherwise, the opposite value is output. Thus, a periodic waveform with a pulse width propor-
tional to the value in the compare register is generated.
Due to the comparison mechanism, the output pulse has a width between zero and 255 PWM
counter cycles. Thus by adding a simple passive filter outside the chip, an analog voltage
between 0 and (255/256) × VDD can be 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.
43.5.3
LCD Interface
The LCD Controller interfaces with the LCD Module through the LCD Interface
(Table 43-12 on
page
885). The 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 sin-
gle scan Mono (Color).
A 4-bit single scan STN display uses 4 parallel data lines to shift data to successive single hori-
zontal 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 hor-
izontal 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.
AT91SAM9263 Preliminary
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6249D–ATARM–20-Dec-07