upd70f3422gj-gae-qs-ax Renesas Electronics Corporation., upd70f3422gj-gae-qs-ax Datasheet - Page 811

• Manufacturer Part Number: upd70f3422gj-gae-qs-ax
• Description: 32-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

LCD Controller/Driver (LCD-C/D)
Connections
Figure 22-2
Table 22-2
Example
Caution
22.1.2 LCD panel addressing
Each individual segment of an LCD panel is addressed by a signal pair: a
segment signal and a common signal. The segment becomes visible when the
potential difference of the corresponding common signal and the segment
signal reaches or exceeds the LCD drive voltage V
Figure 22-2 shows how the eight LCD segments of a digit are allocated to
• two segment signals (SEG
• four common signals
Allocation of segment signals and common signals to LCD segments
(4-time-division)
Every combination of a segment and a common signal addresses a single
element. The middle horizontal bar, for example, becomes visible if the
potential difference of signals SEG
To display a desired pattern on the LCD panel:
1. Check what combination of segment and common signals form the desired
2. Write bit data with the pattern to be displayed to registers SEGREGk.
The LCD Controller/Driver generates the corresponding segment and common
signals.
See also the “Display Example“ on page 818.
At the LCD panel, the signals are connected as follows:
Signals and connections of LCD Controller/Driver
The LCD panel is driven by AC voltage. The performance of the LCD
deteriorates if DC voltage is applied in the common and segment signals. That
means contrast and brightness of the display may decrease. The display may
even be damaged.
Preliminary User’s Manual U17566EE1V2UM00
Signals
segment signals
common signals
display pattern.
SEG
SEG
2n + 1
2n
2n
and SEG
Connection at LCD panel
front surface electrodes
rear surface electrodes
2n+1
and COM1 exceeds V
2n+1,
COM2
COM0
n = 0 to 19)
LCD
.
LCD
.
Chapter 22
COM1
COM3
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