Led display of door head making and debugging

Time:2018-10-30 Views:904

The LED display screen introduced here is a real face circuit.The commodity is of little value.The circuit of the lattice display screen constitutes the lattice display screen, which adopts the method of column scanning and direct transmission of display code. The basic display principle is designed in the following software

Part of this.The display with a resolution of 32x16 is composed of 8 common anode LED lattice units.

Wiring diagram of cascaded LED lattice units.R1 - R16 current limiting electricity is restricted, to protect the LED safety: VTI - VT32 is 32 only PNP transistor. Here, have the effect of switch: made at any time by controlling the BOl - B32 only only conduction to light up the column, when the column switching speed is fast enough, due to the phenomenon of persistence of vision to the human eye, look across the screen is bright, this is tsuen the principle of dynamic scanning.

If the microprocessor has enough power and enough I/o ports, it can directly drive the LED screen.But in order to control it with the AT89552 MCU, some additional drive circuits and decoding circuits are needed to provide enough

Drive capacity well simplify connection with MCU.

The line drive circuit USES two pieces of 74HC245.This is a common driver chip.When DIR receives high power, end A is the input, and end B is the outgoing.

For the column scan circuit, two 4/16 line decoder 74LS154 and u4.u5 correspond to the left and right screens respectively.A,B,C,D are the input end, and yo-y15 is the output end.In addition, there are two lines of CSI and CS2, respectively enabling left and right screen decoders, that is, enabling left and right screens.Cs.cs2 low level enable.

As for the hardware of the lattice display screen, it is difficult to make the LED screen in the rest of the industry. There are 128 flying wires in 8 LED lattice units.Therefore, the production process should be careful and patient enough, do not rush to achieve, take some time to do every day, so that you will not be tired and frequent mistakes.Try to do zero error, otherwise it will be very tedious to check.