BPP-420L Hardware Reference

This page describes the BPP-440's hardware, hookup, configuration and specifications. 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

Product 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 the BPP-440 requires three connections: 5Vdc (regulated), serial input (9600 bps, N81) and ground (connected to both power and the computer/controller).

BPP-440 Serial Interface Board.

Configuration Jumpers

There are two configuration jumpers on the BPP-440 serial interface:

• Dsu (Display Setup): Uncut= Setup Mode; Cut= Write-Protect
• With Dsu uncut/intact, the ESC X0 instruction can be used to store a startup screen (and embedded settings) that will be displayed/executed each time the unit is powered up. When Dsu is cut, changes to the startup screen are prevented.
• This jumper should be cut after the display is configured with an appropriate startup screen.
• If Dsu is cut before the factory-default screen is replaced, it turns off the startup screen/backlight. This matches the startup condition of older BPP-440Ls.
• Spol (Serial Polarity): Uncut=Inverted TTL or RS-232 serial; Cut= Non-inverted TTL (UART-direct) serial
• Leave Spol uncut if BPP is to be used with an RS-232 port (PC com port, or USB adapter with a 9-pin D connector), or in a microcontroller application that outputs inverted serial. That would include applications that previously worked with other Seetron serial LCDs, such as BPI, BPK, BPP, ILM, and VFD-series devices.
• Spol should be cut if the BPP is to be connected directly to a UART-type device, or microcontroller that acts like one, outputting non-inverted TTL serial. This includes inexpensive USB serial adapters that connect via breadboard pins, and many single-board computers (e.g., Arduino) whose documentation states that their serial output is not RS-232 compatible.

Serial Input Electrical Chacteristics

The BPP-440 is directly compatible with both RS-232 and UART-direct serial hookups. This information is provided for the benefit of users who may be interfacing the display to low-voltage or nonstandard logic devices.

The serial input of the BPP-440, shown below, uses an XNOR gate with Schmitt-trigger characteristics. Under logic control (marked Spol Out), the gate is set as inverting or noninverting as needed to deliver the correct data polarity to the controller's UART input. Spol Out also ensures that the serial input is lightly pulled to the idle state (low for inverted input; high for noninverted) to ensure that the input doesn't float when disconnected.

These features reject noise that might otherwise show up as garbage characters on the screen. They also complicate the question of the serial-input logic threshold, since this will depend on the Spol setting and the edge (rising or falling) of the input signal. In the table, 'Transition' refers to the direction of change on the serial input (output of the device driving the BPP-440). The idle-to-start-bit transitions are highlighted.

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

BL_ON Jumper. Shorting the pads marked "BL_ON" wires the backlight on (it is normally controlled by the ctrl-N and ctrl-O instructions).

Bright↑ Jumper. Shorting the pads marked "Bright↑" doubles the backlight current.

Dimensions (in mm)

Total depth (front of screen to highest point on pcb) is 26mm.

Mounting

As mentioned in "Cautions" above, BPP-440 must be mounted behind a transparent window in any permanent installation. If it is not, the screen will be vulnerable to damage from users' fingers (e.g., electrostatic discharge or mechanical stress), moisture, dirt, mechanical damage, etc. Damage of this kind is not covered by warranty.

An inexpensive mounting kit is available for these devices (PN: BEZ-440), but any transparent barrier will suffice.

Specifications