VFD-x20 Hardware Reference

DISCONTINUED: REFERENCE ONLY

This page describes the hardware, hookup, configuration and specifications of the VFD-420 and VFD-220 serial displays. For information on sending data and instructions to the display please see the programmer's reference.

Table of Contents

Hardware

Cautions/Warranty

Connect/Configure

Dimensions

Mounting

Specifications

Other Pages

Index, Revision History

Programmer's Reference

VFD-220 Description

VFD-420 Description

Cautions and Warranty

Handling, Usage and Operating Precautions

• Do not exceed the maximum supply voltage of 5.3Vdc.
• Always ensure that supply polarity is correct.
• If the screen requires cleaning, use low-tack tape to remove dust.
• Do not wipe or scrub the screen; it is easily scratched.
• In a permanent installation, mount the display behind a transparent window.
• Protect the unit from electrostatic discharge (ESD).
• Do not subject the display to sharp impact or mechanical pressure.
• Do not disassemble, drill or modify the unit in any way.
• Do not allow solvents, cleaners, or water to come into contact with the screen.
• Do not operate when wet or under conditions of condensing humidity (dew).

Seetron warrants this product against defects in materials and workmanship for a period of 90 days. If you discover a defect, we will, at our option, repair, replace, or refund the purchase price. Return the product with a description of the problem. We will return your product or its replacement via standard shipping. Expedited shipping is available at the customer's expense. Note: Violating the usage guidelines above, or attempting to repair or modify the module or the serial interface, voids this warranty.

Connection/Configuration

Hooking up a VFD-220 or -420 requires three connections: 5Vdc (regulated), serial input (2400 or 9600 bps, N81) and ground (connected to both power and the computer/controller).

VFD-x20 Serial Interface Board.

Configuration Switches

There are two configuration switches on the serial interface. Always change switch settings with the power OFF; changes take effect next power ON. Functions:

• (1) Configuration Mode: OFF= Normal Operation, ON= Configure the display (software or ESC-W)
• (2) Serial Baud Rate: OFF= 2400bps, ON= 9600bps

Serial Input

VFD-x20 devices accept inverted serial input, such as the output of an *RS-232 port. The direct output of a UART is noninverted; it is not compatible unless inverted (NOT gate). In some cases, workarounds exist to avoid the additional component:

• Basic Stamp SEROUT instructions accept a parameter that inverts the output in software.
• Arduino v1.0+ SoftwareSerial supports inverted output: SoftwareSerial(rxPin, txPin, 1); (where 1 sets inverted output).
• PIC microcontrollers with the "enhanced" USART (EUSART) can be configured for inverted output by setting the SCKP bit of the BAUDCON register during USART initialization.

*RS-232 serial signals often use ±10V signals. These voltages will not harm the serial interface, which has a protective "clamp" circuit on its serial input.

Solder Pads

"Bell" Output. A piezo buzzer may be connected to the pads marked "BELL" on the interface board. The buzzer will beep when the ctrl-G Bell character is received. A compatible buzzer will have these specs:

• 5Vdc operation
• Internal oscillator (buzzer, not a speaker)
• Less than 25mA current draw

Dimensions (in mm)

Total depth (front of screen to highest point on pcb) is 30mm. Back and side-view drawings are TBD.

VFD-420	VFD-220

Mounting

An inexpensive mounting kit is available for VFD-420(PN: BEZ-420). There is no equivalent kit for VFD-220.

Specifications