MC68HC05L28 Datasheet, PDF (73/156 Pages) Motorola, Inc – Flexible general-purpose microcomputer

7
LIQUID CRYSTAL DISPLAY DRIVER MODULE
This chapter describes the generic M68HC05 family LCD driver module. Any differences in the
module specific to the MC68HC05L28 are indicated along with the generic description.
The M68HC05 family LCD driver module can be configured with up to 24 frontplane drivers and a
maximum of 4 backplane drivers. This allows a maximum of 96 LCD segments.
The LCD driver module on the MC68HC05L28 supports 18 frontplanes and 4 backplanes, allowing
a maximum of 72 LCD segments. Each segment is controlled by a corresponding bit in the LCD
RAM. The mode of operation is determined by the values set in the LCD control register at $1E.
At reset or on power-up, the drivers are configured in the default duplex mode, 1/2 bias with 2
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backplanes and 18 frontplanes. Also at power-up or reset the ON/OFF control for the display, the
DISON bit in the LCD control (LCD) register, is cleared disabling the LCD drivers. Figure 7-1 shows
a block diagram of the LCD system.
Internal data bus
8
Internal address bus 13
Internal
signals
Control
logic
LCD
RAM
Segment
driver
BP3
Backplane
BP2
driver
BP1
BP0
Voltage
generator
V_LCD
FP17
FP0
Figure 7-1 LCD system block diagram
MC68HC05L28
LIQUID CRYSTAL DISPLAY DRIVER MODULE
TPG
MOTOROLA
7-1