Matrix Orbital VK204-25 Legacy - Manual (Page 4)

1 Introduction
The VK204-25 comes equipped with the following features;
• 20 column by 4 line text 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 RS-232
• Communication over I
2 C or RS-232
• Use of up to 16 modules on the same 2 wire I
2 C interface
• Fully buffered so that no delays in transmission are ever necessary
• Software controlled brightness
• Display with configurable time-out setting up to 180 minutes
• Use of 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 +7V to +15V or +7V to +30V
• Extended temperature option
• Fits Matrix Orbital’s dual PC Bay inserts without modifications
• Built in large digits
1.1 What to Expect From the VK204-25
The VK204-25 is designed as the display unit for an associated controller. The controller may be any-
thing from a single board, special purpose micro-controller to a PC, depending on the application. This
controller is responsible for what is displayed on the screen of the display.
The display 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 Not to Expect From the VK204-25
The display does not include bitmap graphics capability, except that permitted by defining special char-
acters.
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 display, which acts simply as a matrix to serial converter. To use the
keypad to control the display, the controller must be programmed accordingly.
Matrix Orbital VK204-25 1