40 experiments of single chip microcomputer: left and right movement of advertising lights

1. Experimental task

Move a single light left and right. The hardware circuit is shown in Figure 4.4.1. The eight LEDs L1-L8 are connected to the P1.0-P1.7 interfaces of the single-chip computer. When the output is "0", the LED lights up. At the beginning, P1.0→P1.1→P1.2→P1.3→┅→P1.7→P1.6→┅→P1.0 lights up, and the cycle repeats.

2. Circuit schematic diagram



3. Hardware connection on the system board

Connect P1.0-P1.7 in the "single-chip computer system" area to the L1-L8 ports in the "eight-way LED indication module" area with an 8-core cable. The requirements are: P1.0 corresponds to L1, P1.1 corresponds to L2, ..., P1.7 corresponds to L8.

4. Programming content

We can use the output port instruction MOV P1, A or MOV P1, #DATA. As long as we give the accumulator value or constant value and then execute the above instruction, we can achieve the output control action. [page]

The data sent each time is different. The specific data is shown in Table 1 below:

P1.7	P1.6	P1.5	P1.4	P1.3	P1.2	P1.1	P1.0	illustrate
L8	L7	L6	L5	L4	L3	L2	L1
1	1	1	1	1	1	1	0	L1 Bright
1	1	1	1	1	1	0	1	L2 Bright
1	1	1	1	1	0	1	1	L3 Bright
1	1	1	1	0	1	1	1	L4 Bright
1	1	1	0	1	1	1	1	L5 Bright
1	1	0	1	1	1	1	1	L6 Bright
1	0	1	1	1	1	1	1	L7 Bright
0	1	1	1	1	1	1	1	L8 Bright

Table 1

5. Program flow chart

　 

6. Assembly source program

ORG 0
START: MOV R2,#8
MOV A,#0FEH
SETB C
LOOP: MOV P1,A
LCALL DELAY
RLC A
DJNZ R2,LOOP
MOV R2,#8
LOOP1: MOV P1,A
LCALL DELAY
RRC A
DJNZ R2,LOOP1
LJMP START
DELAY: MOV R5,#20 ;
D1: MOV R6,#20
D2: MOV R7,#248
DJNZ R7,$
DJNZ R6,D2
DJNZ R5,D1
RET
END

7. C language source program

#include
unsigned char i;
unsigned char temp;
unsigned char a,b;

void delay(void)
{
unsigned char m,n,s;
for(m=20;m>0;m--)
for(n=20;n>0;n--)
for(s=248;s>0;s--);
}
void main(void)
{
while(1)
{
temp= 0xfe;
P1=temp;
delay();
for(i=1;i<8 ;i++)
{ a=temp< ;
b=temp>>(8-i); P1 =a|b;
delay
(); }
for
(i=1;i<8;i++) {
a
=temp>> i ;