Microprocessor control with LED digital there are many ways, according to display points, there is a

static display and dynamic (scanning) showed that decoding by decoding methods can be divided into

hardware and software decoding of the sub.
Static display is the display driver circuit with output latch function, MCU will have to display

data, display data and stability,mini flashlight taking up very little CPU time. Dynamic indicate a need for CPU time

on the display device to refresh the data, display data with light flashes, take up more CPU time.
Both have advantages and disadvantages display; static display although the data is stable, taking up

very little CPU time, each display unit requires a separate display driver circuits, hardware more;
Although the dynamic display of light flashes, take up more CPU time, but using less hardware, saving

board space.

Hardware decoding is shown in code segment completed entirely by the hardware, CPU as long as you can

send a standard BCD code, there are certain standards of the hardware connection. Software decoding is

software to complete the hardware features, simple hardware, wiring and flexible display section of

code entirely by the software to process, is commonly used in display driving method.
In addition, the market there are some special LED display module, such as MAX7219 scan driver, etc.,

functions very strong, flashlight slightly higher prices. The following is an example of using 74LS164 driven

display and a display with a 4094 scan driver example:

The case of the figure plus a PNP type transistor to control the digital control of power, because no

data latch end 164, the data in the transmission process, the output is transparent, so that data

transmission process, There are digital control
Flashing phenomenon, driven more digits, flashing is visible. In order to eliminate this phenomenon,

the data transfer process,led flashlight close the transistor so that no electricity is not digital tube display,

data transfer transistor conduction finished soon so that so that to achieve
Latch function. This approach can drive a dozen of 164 displayed without flashing phenomenon.