HD66766R Datasheet, PDF (14/97 Pages) Hitachi Semiconductor – 132 x 176-dot Graphics LCD Controller/Driver for 65K Colors

HD66766R
Rev. 1.0-1 / September 2002
Graphics RAM (GRAM)
The graphics RAM (GRAM) has twelve bits/pixel and stores the bit-pattern data of 132 x 176 bytes.
PWM Grayscale Palette Circuit
The grayscale palette generates a PWM signal, which corresponds to specified grayscale level. Any 65K
out of the 140K possible colors can be displayed at the same time.
Grayscale Control Circuit
The grayscale control circuit performs 16-grayscale control with the pulse width modulation (PWM)
method for grayscale display for each color.
Timing Generator
The timing generator generates timing signals for the operation of internal circuits such as the GRAM.
The RAM read timing for display and internal operation timing by MPU access is generated separately to
avoid interference with one another.
Oscillation Circuit (OSC)
The HD66766R can provide R-C oscillation simply through the addition of an external oscillation-resistor
between the OSC1 and OSC2 pins. The appropriate oscillation frequency for operating voltage, display
size, and frame frequency can be obtained by adjusting the external-resistor value. Clock pulses can also
be supplied externally. Since R-C oscillation stops during the standby mode, current consumption can be
reduced.
Liquid Crystal Display Driver Circuit
The liquid crystal display driver circuit consists of 176 common signal drivers (COM1 to COM176) and
396 segment signal drivers (SEG1 to SEG396).
Display pattern data from GRAM is latched to the 396-bit latch circuit. The latched data then enables the
segment signal drivers to generate drive waveform outputs. The common driver outputs one of the VCH,
VM or VCL voltage level. The SGS bit can change the shift direction of 396-bit data for the segment. The
CMS bit can also change the shift direction for the common by selecting an appropriate direction for the
device-mounting configuration.
When display is off, or during the standby or sleep mode, all the above common and segment signal
drivers output the GND level, halting the display.
LCD drive power supply circuit
LCD drive power supply circuit generates VCH, VSH, VM and VCL voltage level to drive LCD panel.
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