VK202-25 rev. 05
4
1. Introduction
Your VK202-25 has the following features:
20 column by 2 line text fluorescent display
built-in font with provision for up to 8 user-defined characters
Speeds from 1200 bps to a lighting fast 19.2 Kbps over RS232
Communicate over I
2
C or RS232 (with software controlled speed)
Use up to 127 modules on the same 2-wire I
2
C interface
Fully buffered so that no delays in transmission are ever necessary
Add your own Splash/Start-up screen
Software controlled brightness with configurable display time-out setting up to 180 minutes
Use up to a 25 key keypad with a 10 key buffer.
Six general purpose outputs for a variety of applications
Horizontal or Vertical bar graphs
Variable power options, +5V or +9V to +15V
Extended temperature option.
Fits our PC Bay inserts without any modifications
1.1 What it Does
The VK202-25 is designed as the display unit for an associated controller. The controller may be anything
from a single board, special purpose microcontroller to a PC, depending on the application. This controller
is responsible for what you see on the screen of the VK202-25.
The VK202-25 provides a simple command structure to allow text and bar graphs to be displayed on the
screen. Text fonts are built in, and use standard ASCII mapping. Provision is made for up to 8 user-defined
characters.
The screen is luminous for low-light situations. Display may be turned on or off under program control.
Brightness is adjustable to compensate for differing lighting conditions.
General purpose outputs allow the controller to switch up to six electronic or electro-mechanical devices by
issuing commands to the display unit. These can be used for controlling LEDs, relays, etc.
1.2 What it Does Not Do
The VK202-25 does not include bitmap graphics capability, except that permitted by defining special
characters.
1.3 Keypad Interface
The keypad interface takes row/column input and converts it to ASCII characters, which are delivered out
the RS-232 or I
2
C port to the associated controller. Note that the keypad is
not
used to directly control any
aspect of the operation of the VK202-25, which acts simply as a matrix to serial converter. If you want to
use the keypad to control the VK202-25 display you must program your controller accordingly.
1.4 Setup for Testing
Before setting up your application you may want to try out the VK202-25. This is easily done with a PC.
Here's what you'll need:
A power cable with a 4 pin connector (same connector as used to connect 3.5 inch floppy
drive). Do not connect the VK202-25 to an unmodified spare power connector in a PC. To
modify such a cable see section 2.1.1.
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