Display I2C Lcd driver PC8574
I2C Lcd driver PC8574
Driver for lcd display using 2 wire (SDA, SCL)
NGN1,500.00
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Product Details
PCF8574 I2C LCD Driver
Interface Overview
- Expander: PCF8574 (8-bit I/O)
- Display: HD44780 (4-bit mode)
- I2C Address (Common): 0x27 or 0x3F (Check hardware jumpers)
Driver Byte Pinout (P7)
Bit Position | PCF8574 Pin | LCD Signal | Control Role |
7-4 | P7-P4 | D7-D4 | Data Nibble |
3 | P3 | Backlight (BL) | 1 (ON) / 0 (OFF) |
2 | P2 | Enable (EN) | Pulse (Latch) |
1 | P1 | R/W | 0 (Write) |
0 | P0 | RS | 0 (Command) / 1 (Data) |
8-bit Transfer Sequence (4 I2C Writes Total)
To send one full 8-bit command or data byte, you must perform four distinct I2C writes:
Step | Nibble | EN State | I2C Write |
1 | High Nibble | EN = 1 (Set) | Write 1 |
2 | High Nibble | EN = 0 (Latch) | Write 2 |
3 | Low Nibble | EN = 1 (Set) | Write 3 |
4 | Low Nibble | EN = 0 (Latch) | Write 4 |
These are the essential commands (sent as 8-bit bytes using the 4-step sequence above) to start the LCD:
- Initial 8-bit detection: Send high nibble 0x3 (3 times).
- Switch to 4-bit mode: Send high nibble 0x2.
- Function Set: 0x28 (4-bit, 2 lines, 5x8 font).
- Clear Display: 0x01.
- Display ON: 0x0C.
- Entry Mode: 0x06.
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