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User’s Manual U14701EJ3V0UD
CHAPTER 17 LCD CONTROLLER/DRIVER
17.1 LCD Controller/Driver Functions
The internal LCD controller/driver of the
μ
PD780318, 780328, and 780338 Subseries has the following functions:
(1) Automatic output of segment signals and common signals by automatically reading display data memory
(2) Internal booster circuit employed for LCD driver reference voltage generator (
×
3 only).
Therefore, LCD can be stably displayed even if the supply voltage drops because the battery voltage drops.
In addition, the LCD driver reference voltage can be changed by using an external resistor to adjust the
brightness.
(3) Three display modes selectable
Static (up to 12 lines)
1/3 duty (1/3 bias)
1/4 duty (1/3 bias)
(4) Four types of frame frequencies selectable in each display mode
(5) The number of segment signal output lines differs depending on the model as shown in Table 17-1.
Table 17-1. Segment Signals and Common Signals
Part Number
Maximum Number of Segment Signals
Common Signals
μ
PD780316, 780318
24 lines (S0 to S23), of which 12 (S0 to S11)
are selectable for static display.
Dynamic display: COM0 to COM3
Static display: SCOM0
μ
PD780326, 780328
32 lines (S0 to S31), of which 12 (S0 to S11)
are selectable for static display.
μ
PD780336, 780338
40 lines (S0 to S39), of which 12 (S0 to S11)
are selectable for static display.
μ
PD78F0338
40 lines (S0 to S39), of which 12 (S0 to S11)
are selectable for static display, and 16
(S24 to S39) are also used with output port
lines (P80 to P87 and P90 to P97)
Note
.
Note
The operation mode of the alternate-function pins can be switched between the port mode and segment
signal mode in 8-bit units by using pin function switching registers 8 and 9 (PF8 and PF9).
(6) Simultaneous driving of static display (up to 12 segments) and dynamic display. The operation mode of the
alternate-function pins (S0 to S11) can be switched between the static display mode and dynamic display mode
in 4-bit units.
(7) Blinking of LCD (only when subsystem clock is used).
Whether each segment blinks or not can be selected.
The blinking cycle can be selected from 0.5 s or 1.0 s.
(8) Operation with subsystem clock
(9) Operating voltage range: 1.8 to 5.5 V