LCD Controller Registers
11-31
LCD Controller
Table 11–17 shows which set of LCD data pins (and LCD.P pins) is used for
each mode of operation.
Table 11–17. LCD Controller Data Pin Utilization for Mono/Color, Passive/Active Panels
Color/Mono
Passive/Active Panel
Screen Portion
Pins
Mono 2, 4, 8
Passive
Whole
LCD_PIXEL[3:0]
Color 2, 4, 8, 12, 16
Passive
Whole
LCD_PIXEL[7:0]
Color 2, 4, 8, 16
Active
Whole
LCD_PIXEL[15:0]
LCD Enable (LCDEN)
The LCD enable (LCDEN) bit is used to enable and disable LCD controller
operation. When LCDEN = 0, the LCD controller is disabled. When LCDEN =
1, the LCD controller is enabled.
Note:
All other control registers must be initialized before setting LCDEN.
You program LCDControl last, and you can configure all eight bit fields at the
same time via a word write to the register. If the user clears LCDEN while the
LCD controller is enabled, it is permitted to complete transmission of the cur-
rent frame before being disabled. Completion of the current frame is signaled
by the DMA when it sets the frame done bit (Done) within the LCD status
register, which generates an interrupt request.
Table 11–18 shows the location of all seven bit fields located in the LCD control
register (LCDControl). LCDEN is the only control bit that is reset to a known
state, ensuring that the LCD is disabled after a reset of the LCD controller. The
user must program all other control bit fields before setting LCDEN = 1 (a half-
word or word write can be used to configure the whole register while setting
LCDEN) and must also disable the LCD controller when changing the state of
a control bit within the LCD controller.
Note:
Writes to reserved bits are ignored, and reads return 1s.
The LCD timing 0 register contains four bit fields that are used as modulus
values for a collection of down counters, each of which performs a different
function to control the timing of several of the LCD pins.
The LCD controller must be disabled (LCDEN = 0) when changing the state
of any field within this register. The reset state of all bit fields is unknown and
must be initialized before enabling the LCD.