hd66712u Renesas Electronics Corporation., hd66712u Datasheet - Page 53

• Manufacturer Part Number: hd66712u
• Description: Dot-matrix Liquid Crystal Display Controller/driver - Hitachi Semiconductor
• Manufacturer: Renesas Electronics Corporation.

HD66712U
Oscillator Circuit
416
Clock
1) When an external clock is used
(1) 1 /17 duty cycle
(2) 1 /33 duty cycle
OSC1
HD66712
COM1
COM1
Item
Line selection period
Frame frequency
Note: At the calculation example above for displayed frame frequency, all oscillator frequencies are
Item
Line selection period
Frame frequency
Note: At the calculation example above for displayed frame frequency, all oscillator frequencies are
V
V
V1
V4
V5
V1
V4
V5
CC
270 kHz (1 clock = 3.7 s).
CC
270 kHz (1 clock = 3.7 s).
1-line selection period
1-line selection period
1
1
Figure 23 Frame Frequency
Figure 22 Oscillator Circuit
2
2
2) When an internal oscillator is used
5-Dot Font Width
200 clocks
79.4 Hz
5-Dot Font Width
100 clocks
81.8 Hz
Rf
Normal Display Mode (LP = 0)
Normal Display Mode (LP = 0)
3
3
1 frame
4
4
1 frame
OSC1
OSC2
6-Dot Font Width
240 clocks
66.2 Hz
6-Dot Font Width
120 clocks
68.2 Hz
HD66712
16
32
17
33
1
1
5-Dot Font Width
60 clocks
66.2 Hz
5-Dot Font Width
60 clocks
68.2 Hz
2
2
Low Power Mode (LP = 1)
Low Power Mode (LP = 1)
3
3
1 frame
1 frame
i) HD66712S
ii) HD66712U
The oscillator frequency can be
adjusted by oscillator resistance
(Rf). If Rf is increased or power
supply voltage is decreased, the
oscillator frequency decreases.
The recommended oscillator
resistor is as follows.
• Rf = 91 k
• Rf = 75 k
• Rf = 130 k
• Rf = 110 k
6-Dot Font Width
72 clocks
55.1 Hz
6-Dot Font Width
72 clocks
56.8 Hz
16
32
17
33
2% (V
2% (V
2% (V
2% (V
CC
CC
CC
CC
= 5V)
= 3V)
= 5V)
= 3V)