at91sam9263 ATMEL Corporation, at91sam9263 Datasheet - Page 879

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

43.5.2.10
43.5.2.11
6249D–ATARM–20-Dec-07
Display
PWM
HFP
=
f
LCDDOTCK
In monochrome mode, Horizontal_display_size is equal to the number of horizontal pixels. The
number_data_lines is equal to the number of bits of the interface in single scan mode;
number_data_lines is equal to half the bits of the interface in dual scan mode.
In color mode, Horizontal_display_size equals three times the number of horizontal pixels.
In TFT Mode:
The frame rate equation is used first without considering the clock periods added at the end
beginning or at the end of each line to determine, approximately, the LCDDOTCK rate:
With this value, the CLKVAL is fixed, as well as the corresponding LCDDOTCK rate.
Then select VHDLY, HPW and HBP according to the type of LCD used and
page
Finally, the frame rate is adjusted to 70 Hz - 75 Hz with the HFP value:
The line counting is controlled by the read-only field LINECNT of LCDCON1 register. The
LINECNT field decreases by one unit at each falling edge of LCDHSYNC.
This block is used to configure the polarity of the data and control signals. The polarity of all
clock signals can be configured by LCDCON2[12:8] register setting.
This block also generates the lcd_pwr signal internally used to control the state of the LCD pins
and to turn on and off by software the LCD module.
This signal is controlled by the PWRCON register and respects the number of frames configured
in the GUARD_TIME field of PWRCON register (PWRCON[7:1]) between the write access to
LCD_PWR field (PWRCON[0]) and the activation/deactivation of lcd_pwr signal.
The minimum value for the GUARD_TIME field is one frame. This gives the DMA Controller
enough time to fill the FIFOs before the start of data transfer to the LCD.
This block generates the LCD contrast control signal (LCDCC) to make possible the control of
the display's contrast by software. This is an 8-bit PWM (Pulse Width Modulation) signal that can
be converted to an analog voltage with a simple passive filter.
The PWM module has a free-running counter whose value is compared against a compare reg-
ister (CONSTRAST_VAL register). If the value in the counter is less than that in the register, the
876.
×
------------------------------------------------------------------------------------------------------------- -
f
LCDVSYNC
LINEVAL
HOZVAL
LINEVAL
f
lcd_pclk
×
=
(
LINEVAL
=
=
=
(
HOZVAL
Horizontal_display_size 1
Vertical_display_size 1
Vertical_display_size 1
1
+
+
VBP
5
)
×
+
(
f
VFP
lcd_vsync
AT91SAM9263 Preliminary
+
–
–
1
)
–
×
–
(
LINEVAL
(
VHDLY
+
+
VPW
1
)
)
+
VBP
+
“Equation 1” on
HOZVAL
+
879
5
)