Video Wall circuits

80x32 LED matrix display

I recently purchased 10 SLM1608 (SLM1606) LED matrix display units from Ebay (you might also contact the seller directly at op16@gmx.de). These are 16x16 LED matrix units with a green and a red LED per pixel allowing each pixel to be switched to either green, red, amber or off. The goal of this LEDMATRIX project was to build a 80x32 pixel display by arranging the displays in two rows with 5 displays each giving a total of 16*16*2*2*5 = 5120 LEDs to be controlled individually. Fortunately these displays come with interated controllers and the data can be shifted into a single display using as few as 6 digital signals. By multiplexing some of the select signals all 10 displays can be controlled with a total of ten wires. Using a cheap ATmega32 microcontroller all ten displays can easily be controlled and updated in real time...

Video title generator

Want to add video to your next project? This device uses a PIC16F819 and not much else. Getting 20 characters to a line is possible by using the SPI port to generate video. Neat trick, eh? The character set is limited to upper case and a few punctuation marks and uses a 'folded data table' to store the image data in the space available. Input to the device is via 9600 baud RS-232 directly from a computer com port. Since this device was designed as a status display, data is placed on the screen by sending a decimal number to designate the screen location followed by up to 20 characters of text and a carriage return. This allows individual portions of the screen to be updated without disturbing the rest of the screen display...

Rotating Message board using PIC12F629

A simple rotating display. Just spin and enjoy. While the "Air display" is rotating, it writes the message on the air. Because the "persistence of the vision", you will be able to read the message. The operation is super simple and you don't need an user manual. Press the button to turn it on. Press the button to change the message and press the button to turn it off...

1 to 5 Video splitter

The circuit is based on the type EL2020 (or similar) operational amplifier which is marled by large bandwidth. The LL2020 amplifies the video signal applied to the input stage, with a gain adjustment range of ±6 dB. Output transistor Q1, a 2N3866, applies the video signal to the five outputs designed to drive loads with 75-? impedance...

The GX434 is a high performance low cost monolithic 4x1 video multiplexer incorporating four bipolar switches with a common output, a 2 to 4 address decoder and fast chip select circuitry. The chip select input allows for multi-chip paralleled operation in routing matrix applications. The chip is selected by applying a logic 0 on the chip select input...

The GY4102A is a bipolar, monolithic SPDT video switch incorporating fast control logic. The analog signal path is characterised by low differential gain, low differential phase and low insertion loss, coupled with a ±0.1 dB bandwidth of typically 100 MHz into a 10 pF load, using an external series resistor. ..

The eight SDI input stages use the new GENLINX¾II GS9024 Equalizer IC. Input Return Loss of the PCB is optimized by using R-L circuits at each input. Each GS9024 performs high quality signal equalization over a wide range of data rates from as low as 30 Mb/s to well over 540 Mb/s. They allow the use of very long cable lengths that not only meet but exceed industry SDI expectations. The Equalizers also boast such features as signal strength indication, output data muting and High Z output control that is useful for multiplexing applications...

The GX4201 is a wideband 1x1 video crosspoint implemented in bipolar monolithic technology. The device is characterized by excellent differential gain and phase in the enabled state, and very high off-isolation in the disabled state. The fully buffered unilateral signal path ensures negligible output to input feedback while delivering minimal output switching transients through make-before-break switching...

The GB4550 and GB4550A are high performance monolithic video buffer/clamps made on Gennum's LSI process. They feature a wideband differential amplifier that can be configured as a gain stage. The output signal voltage is limited to +2V above the clamp level in order to prevent damage to crosspoints connected to the output. The clamping level can be set for normal sync tip clamping by connecting pin 4 to -0.286 volts. For other applications, the clamping voltage level can be varied from -5.5 to +5.5 volts...

In order to assist the video design engineer in using Gennum's GX4201 video crosspoint, an AC equivalent circuit has been created. A PSpice® netlist of the circuit has been generated and is available on floppy disk. The equivalent circuit is for AC steady state and transient analysis only. Noise and distortion or DC characteristics cannot be predicted with this model. The data accurately predicts the input and output impedances and transfer characteristics of the devices up to 500 MHz with load capacitances ranging from 10 pF to 100 pF...

The modular multiplexers described in this application note, take these, as well as other points, into consideration and provide an optimal solution for the video design engineer. The 16x1 circuits are realised using four Gennum GX434 or GX214, 4x1 crosspoint ICs and two CMOS logic control ICs...

The 8x1 module uses a CMOS 74HC237 combination 3 to 8 decoder/latch for crosspoint selection, the 10x1 module uses a Motorola MC14028B BCD-to-decimal decoder...