1336
6437E–ATARM–23-Apr-13
SAM9M11
Vertical to Horizontal Delay (VHDLY): The delay between the falling edge of LCDVSYNC and
the generation of LCDHSYNC is configurable in the VHDLY field of the LCDTIM1 register.
The delay is equal to (VHDLY+1) LCDDOTCK cycles.
Horizontal Pulse Width (HPW): The LCDHSYNC pulse width is configurable in HPW field of
LCDTIM2 register. The width is equal to (HPW + 1) LCDDOTCK cycles.
Horizontal Back Porch (HBP): The delay between the LCDHSYNC falling edge and the first
LCDDOTCK rising edge with valid data at the LCD Interface is configurable in the HBP field
of the LCDTIM2 register. The delay is equal to (HBP+1) LCDDOTCK cycles.
Horizontal Front Porch (HFP): The delay between end of valid data and the generation of the
next LCDHSYNC is configurable in the HFP field of the LCDTIM2 register. The delay is equal
to (HFP+VHDLY+2) LCDDOTCK cycles.
There is a limitation in the minimum values of VHDLY, HPW and HBP parameters imposed by
the initial latency of the datapath. The total delay in LCDC clock cycles must be higher than or
formula:
49.6.2.9
Equation 1
where:
VHDLY, HPW, HBP are the value of the fields of LCDTIM1 and LCDTIM2 registers
PCLK_PERIOD is the period of LCDDOTCK signal measured in LCDC Clock cycles
The LCDVSYNC is asserted once per frame. This signal is asserted to cause the LCD's line
pointer to start over at the top of the display. The timing of this signal depends on the type of
LCD: STN or TFT LCD.
In STN mode, the high phase corresponds to the complete first line of the frame. In STN mode,
this signal is synchronized with the first active LCDDOTCK rising edge in a line.
In TFT mode, the high phase of this signal starts at the beginning of the first line. The following
timing parameters can be selected:
Vertical Pulse Width (VPW): LCDVSYNC pulse width is configurable in VPW field of the
LCDTIM1 register. The pulse width is equal to (VPW+1) lines.
Vertical Back Porch: Number of inactive lines at the beginning of the frame is configurable in
VBP field of LCDTIM1 register. The number of inactive lines is equal to VBP. This field should
be programmed with 0 in STN Mode.
Vertical Front Porch: Number of inactive lines at the end of the frame is configurable in VFP
field of LCDTIM2 register. The number of inactive lines is equal to VFP. This field should be
programmed with 0 in STN mode.
There are two other parameters to configure in this module, the HOZVAL and the LINEVAL
fields of the LCDFRMCFG:
HOZVAL configures the number of active LCDDOTCK cycles in each line. The number of
active cycles in each line is equal to (HOZVAL+1) cycles. The minimum value of this
parameter is 1.
VHDLY
HPW
HBP
3
++
+
() PCLK_PERIOD
×
DPATH_LATENCY
≥