Bus Pirate v3 LCD adapter hardware design

From DP

Control HD44780 LCDs from the Bus Pirate v3 with this breakout board. The Bus Pirate LCD mode uses an adapter because there aren't enough pins to directly control a character display.

You can build the adapter with a few parts and a bread board, or you can buy it ready-made at Seeed Studio for $xx.xx. Includes a short connector cable. Every sale directly supports open source development of the Bus Pirat

You can get a Bus Pirate LCD adapter v3 for $9.

Read about the design below.

Contents 1 Overview 2 Hardware 2.1 '595 serial shift register 2.2 Contrast 2.3 Brightness 2.4 HD44780 header 2.5 Bus Pirate v3 IO header 3 PCB 3.1 Partslist 4 Get one!

Overview

Since the Bus Pirate v3 doesn't have enough pins to drive the HD44780 directly, we had to add a serial shift register to drive it. The board also features hardware Contrast, and Brightness adjustment, as well as software controllable backlight.

Hardware

Click for a full size schematic image. Schematic and PCB were designed with the freeware version of Cadsoft Eagle, download the latest project files from our Google Code project page.

'595 serial shift register

To successfully control the LCD, more pins needed to be added. We tackled this problem by adding the '595 8bit serial shift registrar (IC1), which is decoupled with the 0.1uf capacitor (C1), and also drives the LED (LED1) trough a 1k resistor (R1). It controls the LCD in the 4bit mode, using 4 pins of the '595's output for the D7-D4 LCD pins, and another 3 for the LCD's control pins. The LED (LED1) is driven by the 8th pin of the '595.

Contrast

The contrast 50K trimmer is used to adjust the contrast of your LCD. Turnong it in the counter-clock wise direction will increase the contrast.

Brightness

HD44780 header

Included on the board is the standard 16pin header for HD44780, and compatible LCDs.

Bus Pirate v3 IO header

For simple connectivity, the same 10pin IO header as featured on the Bus Pirate v3 is located on the board. All it takes to connect the two boards is a 10pin flat cable.

PCB

We used the freeware version of Cadsoft Eagle to make the schematic and PCB. Download the latest designs and firmware from the project Google Code page.

• PCB and placement notes
• soldering advise

Partslist

Click for a full size placement image.

partlist

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Get one!

You can [get one for $00], including worldwide shipping.

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