HD4074329S Renesas Electronics America, HD4074329S Datasheet - Page 68

• Manufacturer Part Number: HD4074329S
• Description: MCU 4-Bit HMCS400 CISC 20KB EPROM 3.3V/5V 64-Pin SDIP
• Manufacturer: Renesas Electronics America

Specifications of HD4074329S

• Package: 64SDIP
• Family Name: HMCS400
• Maximum Speed: 4.5 MHz
• Ram Size: 268 Byte
• Program Memory Size: 20 KB
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 4 Bit
• Program Memory Type: EPROM
• Number Of Programmable I/os: 35
• On-chip Adc: 4-chx8-bit
• Operating Temperature: -20 to 75 °C
• Number Of Timers: 3

HD404328 Series
LCD Output Register (LOR: $015): Write-only register used to specify that ports R2–R5 act as pins
SEG1–SEG16, as shown in table 32.
Table 32
LOR
Bit 3
0
1
Large Liquid-Crystal Panel Drive and V
the built-in division resistors by attaching external resistors in parallel, as shown in figure 40.
Since HD404328U and HD4074329U do not have built-in division resistors, they require external LCD
voltage division resistors for voltage adjustment.
The size of these resistors cannot be simply calculated from the LCD load capacitance because the matrix
configuration of the LCD complicates the paths of charge/discharge currents flowing through the
capacitors—and the resistance will also vary with lighting conditions. This size must be determined by
trial-and-error, taking into account the power dissipation of the device using the LCD, but a resistance of 1
k
Always turn off the power switch (set bit 1 of the LCR to 0) before changing the liquid-crystal drive
voltage (V
64
F.)
to 10 k would usually be suitable. (Another effective method is to attach capacitors of 0.1 F to 0.3
Port Selection
R5
SEG16–SEG13
LCD
LCD Output Register
).
LOR
Bit2
0
1
Port Selection
R4
SEG12–SEG9
LCD
: To drive a large-capacity LCD, decrease the resistance of
LOR
Bit 1
0
1
Port Selection
R3
SEG8–SEG5
LOR
Bit 0 Port Selection
0
1
R2
SEG4–SEG1