USB & serial LCD backpack

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USB & serial LCD backpack
Codename PIC LCD backpack
Status Test production
Development development forum
ID # {{{id}}}

Prototype PCBs are available in the free PCB drawer.

This is a USB and serial backpack for simple HD44780 character LCD screens. It has a few nice features that set it apart from the serial-only LCD backpacks at SparkFun and Adafruit:

  • USB and serial control of characters LCDs
  • Supported in common software (LCD Smartie) as 'matrix orbital' display
  • Adjust contrast and backlight from software
  • Couple extra pins for buttons
  • 500mA fuse
  • USB upgradable

We like this project, but we probably won't produce it because HD44780 LCDs aren't very popular anymore. If you'd like a PCB (and plan to build it) please let us know in the comments.

Slightly more on the wiki. Firmware and hardware are in SVN.


Contents

Overview

History and related links

Download

Prototypes

Pic-lcd-backpackv2 .jpg

Hardware

Cct-LCD-Backpack-PIC-HD44780-v1a.png

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

Project-section-diagram-490.jpg

  • Microcontroller
  • Power and decoupling
  • Oscillator
  • Programming and reset support
  • LEDs

Another part of it

Project-section-diagram-490.jpg

PCB

PIC-lcd-backpack-pcb.jpg

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

PIC-lcd-backpack-HD44780-v1a-brd.png

PIC HD44780 LCD backpack
PartQuantityValuePackage
BACKLIGHT1100RB25P
C1,C2227pfC0805
C31220nFC0805
C410.1uFC0805
CONTRAST110KB25P
D11BAS16JSOD2514X100N
F11500mARCL_L1812
IC11PIC18F2550_28WSO28W
ICSP11X05
J11USBSMDUSB-MINIB
LCD11X16
Q1120MHzHC49UP
R1110kR0805
R211KM0805
RB4,RB521X01
SJ11SJ_2
T11BC818SOT23-BEC
UART,USB21X04

The latest sources and distributors are in the master partlist. See something missing? Please let us know.

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

The controller implements a (subset) of the serial interface provided by Matrix Orbital Serial LCDs.

To send a command, first send the START_COMMAND byte (0xFE), followed by the command (with any parameters), followed by the END_COMMAND byte (0x9A).

For example, to turn on the backlight, send 0xFE, 0x42, 0x00, 0x9A.

Name Decimal Hex Parameters
MATRIX_ORBITAL_COMMAND 254 0xFE None
BACKLIGHT_ON 66 0x42 1 (minutes, 00=forever)
BACKLIGHT_OFF 70 0x46 None
CLEAR 88 0x58 None
HOME 72 0x48 None
POSITION 71 0x47 2 (col, row)
UNDERLINE_CURSOR_ON 74 0x4A None
UNDERLINE_CURSOR_OFF 75 0x4B None
BLOCK_CURSOR_ON 83 0x53 None
BLOCK_CURSOR_OFF 84 0x54 None
BACKLIGHT_BRIGHTNESS 152 0x98 1 (brightness)
CUSTOM_CHARACTER 78 0x4E 9 (character #, 8-byte bitmap)
NETWORK_CONFIG 153 0x99 None
END_COMMAND 154 0x9A None

Bootloader

490px

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!

Links

License