The Really Brief Guide on:
The Spyglass User Interface Board

Written by Pascal Stang | Updated: Sunday February 20, 2011

Spyglass UI Board Front
Spyglass UI Board Back

Spyglass UI Features:

Spyglass UI Pinout:

The pinout is shown looking into the connector on the back.

+5V
Pin 1
X X 2
+5V
I2C SCL
3

X

X 4
GND
I2C SDA
5
X X 6
GND
NC
7
X X 8
Beeper +5V
NC
9
X X 10
NC

How to operate the Spyglass UI:

The Spyglass UI Board is controlled via three (3) PCF8574 I2C 8-bit I/O expanders, and one 8-bit I2C DAC. The parts are as used as follows:

Part
I2C Address
Function
PCF8574 #1
0x40
Reading the pushbuttons

PCF8574 #2

0x42
Controlling the LCD data lines DB0-7
PCF8574 #3
0x44
Controlling the LCD control signals RS, R/W, E,
and the LEDs and piezo beeper
MAX518 DAC
0x58
Controlling LCD Contrast

Each PCF8574 has 8 I/O pins which can be read and written via the I2C bus. Here is how they are connected.

Part (I2C address)
I/O pin #
Function/Connection
PCF8574 #1 (0x40)
P0-6
Pushbuttons S1-7

 

P7
Not connected

PCF8574 #2 (0x42)

P0-7
LCD Data Lines DB0-7

PCF8574 #3 (0x44)

P0

LED D2

 

P1

LED D3

 

P2
Beeper

 

P3
Not connected

 

P4
Not connected

 

P5
LCD Control Line RS

 

P6
LCD Control Line RW

 

P7
LCD Control Line E
-
-
-

Datasheets for select parts:

Example source code:


Written by Pascal Stang | Updated: Sunday February 20, 2011