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)
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)
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
