Advertising panel

Moving adversitment messages with various effects are displayed on LED array.

CPU module

This is general purpose single board computer based on Z80A CPU with the following features:

ASIO for RS232 communication. Two channel sync/async
PIO for general purpose use
RTC with CMOS RAM for time configurations
XT/AT keyboard connector
up to 32k ROM
up to 32k SRAM with battery backup
watch dog timer
general purpose wire wrap area

Display module

Consists solely from an array of high intensity LED diodes driven by horizontal and vertical module. Display is designed in such way that the length of the panel can be variable. Normally 3 to 5 display PCBs are conected together.

rp$disp.pcb | eps

Horizontal module

Multiplexing of rows is driven by horizontal module by high power FET transistors capaple to whitstand the current of the single row of LEDs. The brightness of display is automaticly regulated by phototransistor. This means that during the day the brightness is high and low at dark. Horizontal module also genrates clock for row select and generates interrupt to the CPU and signals row 0 for synchronisation. Multiplexing is thus implemented fully in hardware. This prevents that display LEDs get burned by static overdrive. CPU is acting as slave to the horizontal module.