ST7625 Datasheet, PDF (39/160 Pages) Sitronix Technology Co., Ltd. – 65K Color Dot Matrix LCD Controller/Driver

ST7625
7.4 Gray-Scale Display
ST7625 incorporates a 4FRC & 31 PWM function circuit to display a 64 gray-scale display.
7.5 Oscillation circuit
ST7625 has a built-in an oscillator circuit. It provides internal clock without using external resistor. This oscillator signal is
used in the voltage converter and display timing generation circuit.
7.6 Display Timing Generator Circuit
This circuit generates some signals for displaying LCD. The display clock, which is generated by oscillation clock,
generates the clock for the line counter and the signal for the display data latch. The line address of on-chip RAM is
generated in synchronization with the display clock and the display data latch circuit latches the 96-bits display data in
synchronization with the display clock. The display data, which is read to the LCD driver, is completely independent of the
access to the display data RAM from the microprocessor. The display clock generates an LCD AC signal (M), which
enables the LCD driver to make an AC drive waveform, and also generates an internal common timing signal and start
signal to the common driver. The frame signal or the line signal changes the M by setting internal instruction. Driving
waveform and internal timing signal are shown in Figure 7.5.
Figure 7.5 2-frame AC Driving Waveform (Duty Ratio: 1/96)
Ver 1.6
39/160
2008/07