20T202DA1J Pacer Components, 20T202DA1J Datasheet - Page 11

• Manufacturer Part Number: 20T202DA1J
• Description: Vacuum Fluorescent Display Module
• Manufacturer: Pacer Components

2X20 LCD Compatible VFD Module
5.2 Interfacing to the MPU
5.3 Reset Function
5.3.1 Power-on Reset Function
RS
E
DB7
DB6
DB5
DB4
5.3.2 Software Reset
For 4-bit interface data, only four bus lines (DB4 to DB7) are used for transfer. When to use 4-bit parallel data transfer,
DB0 to DB3 keep "H" or "L" ("L" in this module). The data transfer between the VFD module and the MPU is
completed after the 4-bit data has been transferred twice. As for the order of data transfer the four high order bits (D4
to D7) are transferred before the four low order bits (D0 to D3).
An internal reset circuit automatically initializes the module when the power is turned on. The following instructions
are executed during the initialization.
(1) Display clear
(2) Set the address counter to 00H
(3) Display on/off control:
(4) Entry mode set:
(5) Function set
(6) CPU interface type
When the user want to RESET the module without turning off the power supply, input both "RST" and "Add" bit high
level while giving low level to the others. Please refer to "Fig.-3 CLK and Reset Command Write-in Detail" for
particular information about software reset. The reset function will be the same as the power-on reset.
This VFD module MPU interface operates in two 4-bit (DB4 to DB7) in M68 type.
* Fill the DD-RAM with 20H (Space Code)
* Set the address counter (ACC) to point DD-RAM.
* D = 0................................... Display off
* C = 0................................... Cursor off
* B = 0................................... Blinking off
* I/D = 1................................ Increment by 1
* S = 0....................................No shift
* IF = 0 ................................. 4-bit interface data
* N = 1 .................................. 2-line display
* BR0 =0, BR1 =0................. Brightness = 100%
* MPU = 1..........................…M68 type
Instruction Register
Write-in
IR7
IR6
IR5
IR4
IR3
IR0
IR2
IR1
Character Code
Write-in
D6
D7
D5
D4
Fig.-11 4-bit Transfer Example (M68)
D3
D2
D1
D0
20T202DA1J (Rev. 3.0)
Page - 11 of 17
Instruction Register
Write-in
IR7
IR6
IR5
IR4
IR3
IR0
IR2
IR1
Character Code
D6
Write-in
D7
D5
D4
D3
D2
D1
D0
Character Code
Write-in
D7
D6
D5
D4
D3
D2
D1
D0