Nokia color LCD backpack design overview
From DP
We've always liked the Nokia knock-off displays from SparkFun. They're dirt cheap ($15) and pretty easy to control.
The goal of this project is to add simple USB control.
You can get a [project for $20], including worldwide shipping.
Read about the design below.
Contents |
Overview
This is a simple USB backpack for SparkFun's cheap color LCDs. Screen contrast and backlight brightness are adjustable from software. A small booster supplies 7volts for the backlight. A PIC 18F24J50 controls the LCD from a USB connection, and a small booster steps the ~5volt USB supply to 7volts.
Our example uses a simple USB->serial interface, but HID and other device types are possible.
Production was stalled for months because we couldn't find a suitable LCD supplier. Eventually we asked SparkFun and they shared a source (Thanks SparkFun!).
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.
Microcontroller section
- Microcontroller
- Power and decoupling
- Oscillator
- Programming and reset support
- LEDs
Another part of it
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.
| Part | Quantity | Value | Package |
|---|---|---|---|
| C1,C2 | 2 | 27pf | C0805 |
| C3 | 1 | 150pF (270pf @55kHz) | C0805K |
| C4,C5,C6,C8 | 4 | 0.1uF | C0805 |
| C7 | 1 | 0.1uF | C0805K |
| C9 | 1 | 0.1uF/50V | C0805K |
| C10 | 1 | 1uF | C0805 |
| C11 | 1 | 10uF/14+v | SANYO-OSCON_SMD_A5 |
| C12,C13,C14 | 3 | 10uF | SMC_A |
| D1 | 1 | 1N5819 | SOD123 |
| IC1 | 1 | PIC18F24J50 | SSOP28 |
| IC2 | 1 | MC34063AD | SO08 |
| J1 | 1 | USBSMD | USB-MINIB |
| JP1 | 1 | 1X05 | |
| L1 | 1 | 100mA+ | L0805 |
| L2 | 1 | 680uH/0.12A | L4532P |
| LCD1 | 1 | NOKIA6100_LCD | NOKIA6100_LCD |
| Q1 | 1 | 16MHz | HC49UP |
| R1 | 1 | 10K | M0805 |
| R2 | 1 | 18K | M0805 |
| R3 | 1 | 2R4 | M0805 |
| R4 | 1 | 180R | M0805 |
| R5 | 1 | 3.9K | M0805 |
| R6 | 1 | 1K | M0805 |
| T1 | 1 | SOT23-BEC | |
| VR1 | 1 | V_REG_LDOSMD | SOT23-5 |
Firmware
The firmware is written in C and compiled with the free Microchip C18 compiler. You can download the latest files from our Google Code project page.
- Operating modes
- extra software required
We used the Microchip USB stack to run the 18F2550 as a virtual serial port. Microchip's code is open but not redistributable. If you want to compile the source, download the stack from Microchip, then drag the source code into the install directory. See the detailed instructions in the PIC compiler how-to.
.inf installation
The virtual serial port (CDC) is an open standard, it should work on any modern operating system.
You don't need a driver, but you will need a .inf file to tell Windows how to use the device. A suitable .inf is included in the project archive.
Commands
Bootloader
Source and license
Taking it further
Here's some ideas for the future:
- List
We'll post the most recent firmware updates on our blog. You can also join the discussion in the [forum].
Get one!
You can [get one for $00], including worldwide shipping.
Your purchases at Seeed Studio keep the open source project coming, we sincerely appreciate your support!