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DFRobot FIT0127 LCD Character Display Specification

1. Overview

The DFRobot FIT0127 is a family of HD44780-compatible character LCD modules commonly used in embedded systems and hobbyist projects. These displays provide alphanumeric output using a dot-matrix character generator and support both 8-bit and 4-bit parallel interfaces.

FIT0127 modules are frequently paired with microcontrollers and 8-bit CPUs such as the 6502, AVR, PIC, and Arduino platforms.

2. General Characteristics

Feature Description
Display type Character LCD (STN, Yellow-Green backlight typical)
Controller HD44780 or compatible
Interface Parallel (4-bit or 8-bit)
Character size 5 x 8 dot matrix
Operating voltage 5 V logic (some variants support 3.3 V)
Backlight LED (separate power pins)
Viewing mode Transflective

3. Display Variants

The FIT0127 designation is commonly associated with 16x2 character LCD modules.

Variant Characters
FIT0127 16 columns x 2 rows

4. Pin Configuration

4.1 Pinout (Standard 16-pin Header)

Pin Name Description
1 VSS Ground
2 VDD +5 V supply
3 VO Contrast adjust
4 RS Register Select
5 R/W Read/Write select
6 E Enable
7 D0 Data bit 0
8 D1 Data bit 1
9 D2 Data bit 2
10 D3 Data bit 3
11 D4 Data bit 4
12 D5 Data bit 5
13 D6 Data bit 6
14 D7 Data bit 7
15 A Backlight Anode (+)
16 K Backlight Cathode (-)

5. Electrical Characteristics (Typical)

Parameter Value
Logic voltage (VDD) 4.5 - 5.5 V
Logic current ~1-2 mA
Backlight voltage ~4.2 V
Backlight current 15-30 mA

6. Interface Signals

6.1 RS (Register Select)

RS Function
0 Instruction register
1 Data register

6.2 R/W

R/W Operation
0 Write to LCD
1 Read from LCD

6.3 Enable (E)

  • Data is latched on the falling edge of E
  • E must be pulsed HIGH � LOW for each transfer

7. Data Bus Operation

7.1 8-bit Mode

  • Uses D0-D7
  • Faster operation

7.2 4-bit Mode

  • Uses D4-D7 only
  • Data transferred in two nibbles (high first)
  • Saves I/O pins

8. Internal Memory Map

8.1 DDRAM (Display Data RAM)

Address Display Position
0x00-0x0F Line 1, Col 1-16
0x40-0x4F Line 2, Col 1-16

8.2 CGRAM (Character Generator RAM)

  • Supports up to 8 custom characters
  • Each character uses 8 bytes

9. Instruction Set (Summary)

Instruction Description
0x01 Clear display
0x02 Return home
0x04-0x07 Entry mode set
0x08-0x0F Display on/off control
0x10-0x1F Cursor/display shift
0x20-0x3F Function set
0x40-0x7F Set CGRAM address
0x80-0xFF Set DDRAM address

10. Initialization Sequence (4-bit Mode)

Wait >15 ms after VDD rises
Function set: 0x33
Function set: 0x32
Function set: 0x28 (4-bit, 2-line)
Display ON/OFF: 0x0C
Entry mode: 0x06
Clear display: 0x01

11. Timing Characteristics (Typical)

Operation Time
Enable pulse width ≥ 450 ns
Command execution ~37 µs
Clear / Home ~1.52 ms

12. Typical System Integration (6502 Example)

RS  � VIA output
E   � VIA output
D4-D7 � VIA Port B
R/W � Grounded (write-only)

13. Contrast and Backlight Control

  • Contrast adjusted via potentiometer on VO pin
  • Backlight may require series resistor
  • PWM dimming supported via external control

14. Absolute Maximum Ratings (Summary)

Parameter Rating
VDD -0.3 V to +6.0 V
Input voltage -0.3 V to VDD + 0.3 V
Operating temp -20 °C to +70 °C

15. Common Use Cases

  • Status displays
  • Debug output for SBCs
  • User interfaces for embedded systems
  • Retrocomputer front panels

16. References