2 layers
Nrf bga
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12 parts14kMIT
2 layers23 × 48 mm
HD44780 i2c
MayaPosch/HD44780_i2c3HD44780-compatible I2C adapter for 5V & 3.3V I2C buses.
- Size
- 23 × 48 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 12
- Nets
- 28
- Pads
- 71
- Tracks, vias
- 147, 17
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 10 May 2021
- Updated
- 7 Jan 2022
Overview
HD44780 i2c is an open-source printed circuit board by MayaPosch, from the MayaPosch/HD44780_i2c repository on GitHub, published under the BSD-3-Clause licence. It is a 2-layer board of 23 × 48 mm with 12 parts on 28 nets, routed with 147 tracks and 17 vias.
Its parts include 4 connectors, 3 resistors, 1 capacitor, 1 IC and 1 transistor.
README
README.mdHD44780-compatible I2C adapter
This project is an I2C expander module based around a Texas Instruments TCA6416A I2C GPIO expander. It allows for interfacing with a variety of 14 to 16-pin, HD44780-compatible displays:
- 14-pin without backlight.
- 16-pin with A/K backlight pins after pin 14.
- 16-pin with A/K backlight pins before pin 1.
- 16-pin with Vee negative bias voltage output on pin 16 instead of backlight ground.
This adapter is compatible with both 3.3V and 5V I2C bus levels. The 5-pin MCU/MPU side header has the following connections:
- Vlcd: LCD-side voltage. This is 5V for a 5V display.
- GND: Ground connection.
- VDD: I2C bus voltage. This is 3.3V for a 3.3V MCU.
- SDA: I2C data line. At MCU level voltage.
- SCL: I2C clock line. At MCU level voltage.
I2C address
Default I2C 7-bit address is 0x20, set with JP1 (1-2 connected). To use the alternate 0x21 address, cut the connection on JP1 between pads 1 & 2, and connect 2-3.
GPIO header
Four GPIO pins from the I2C expander are broken out into a 5-pin header (J3). These can be freely used, limited by the TCA6416A's capabilities.
Vlcd-Vee backlight
When a display is connected that does not use pin 16 for Vee (negative bias), but instead expects a 5V backlight supply voltage on this, connect the Vlcd-Vee connector with a jumper.
Backlight enable
The backlight on/off state is controlled by GPIO 0 of the TCA6416A via Q1.
Contrast adjustment
For contrast adjustment, a potentiometer on the board is provided.
TODO
This is currently a prototype design. It's likely that some things may not fully work as intended yet.
Parts
12| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | 4k7 | Resistor_SMD:R_0603_1608Metric | R1, R2, R3 |
| 1 | 100nF | Capacitor_SMD:C_0603_1608Metric | C1 |
| 1 | Conn_01x02_Male | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Horizontal | J2 |
| 1 | Conn_01x05 | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | J3 |
| 1 | Conn_01x05_Male | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Horizontal | J1 |
| 1 | Conn_01x18_Male | Connector_PinHeader_2.54mm:PinHeader_1x18_P2.54mm_Vertical | J4 |
| 1 | Q_NPN_BCE | Package_TO_SOT_SMD:SOT-23 | Q1 |
| 1 | R_POT_Small | Potentiometer_SMD:Potentiometer_Bourns_TC33X_Vertical | RV1 |
| 1 | SolderJumper_3_Bridged12 | Jumper:SolderJumper-3_P1.3mm_Bridged12_Pad1.0x1.5mm_NumberLabels | JP1 |
| 1 | TCA6416APWR | Package_SO:TSSOP-24_4.4x7.8mm_P0.65mm | IC1 |
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Questions
How big is the HD44780 i2c PCB?
It measures 23 × 48 mm and has 2 copper layers, 1.6 mm thick.
What parts does the HD44780 i2c use?
12 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the HD44780 i2c KiCad files?
From the MayaPosch/HD44780_i2c repository on GitHub, at the commit this page was made from: the board is HD44780_i2c.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the HD44780 i2c design in my own project?
Its repository publishes it under the BSD-3-Clause licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).