LED light module developed by 51 single chip microcomputer

3.1 LED Light Module

3.1.1 LED Schematic Diagram

Figure 3-1-1 LED lamp schematic diagram

The LED light module is connected to the IO port of the microcontroller through the 74573 latch chip, and shares the IO port with the digital tube.

On the development board, you need to use a cable to connect the J12 pin header to the P0 port.

Figure 3-1-3

3.1.2 74HC573 Latch Introduction

The 74HC573 is a transparent latch with eight outputs and three output states.

Latching is to temporarily store the signal to maintain a certain level state.

Figure 3-1-4

When OE is high, the output is always in high impedance state. At this time, the chip is in an uncontrollable state. In general applications, OE must be connected to a low level.

LE is the output state change enable terminal. When LE is low, the output terminal Q always maintains the last stored signal (input from the D terminal). When LE is high, Q follows the state change of D and latches the state of D. That is to say, when the latch enable terminal LE is high, the latch of these devices is transparent to the data (that is, the output is synchronized). When the latch enable becomes low, the data that meets the setup time and hold time will be latched.

3.1.3 Example Code

When the latch is configured in the pass-through state (LE=1), the implemented flash code is:

#include //Add the general 51 MCU header file

#include

void DelayMs(int ms);

int main(void){    

while(1) { P0=0x0; DelayMs(500); P0=0xFF; DelayMs(500); }} 

void DelayMs(int ms){     

int i; unsigned char a,b;    

 for(i=0;ifor(b=199;b>0;b--)               

for(a=1;a>0;a--); }}