[PIC] Expanding input ports with 74HC165 and output with 74hc595

Code C - [expand]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
//////////////////////////////////////////////////////////////////////////////
// READING 74HC165 AND WRITING 74HC595 SHIFT REGISTERS WITH PIC18F4550
//////////////////////////////////////////////////////////////////////////////
 
//////////////////////////////////////////////////////////////////////////////
// NUMBER OF 74HC165s IN YOUR CIRCUIT (change to whatever you want)
//////////////////////////////////////////////////////////////////////////////
const int number_of_74hc165s =1;
 
#define latch_pin LATA.F5 // 74HC165 PIN #1
#define clock_pin LATA.F4 // 74HC165 PIN #2
#define data_pin PORTA.F3 // 74HC165 PIN #9
 
#define shift_register PORTA.F2 // 74HC595 PIN #11
#define storage_register PORTA.F1 // 74HC595 PIN #12
#define serial_data PORTA.F0 // 74HC595 PIN #14
 
unsigned char buttons[number_of_74hc165s * 8];
 
void write_outputs_595(char* value) {
unsigned int i = 0;
 
while(i < 8) {
if(value[i] == '1')
serial_data = 1;
else
serial_data = 0;
 
shift_register = 1;
shift_register = 0;
i++;
}
storage_register = 1;
storage_register = 0;
}
 
void read_inputs_165(int number_of_shift_registers) {
unsigned int m = 0;
 
latch_pin = 0;
latch_pin = 1;
 
while(m < number_of_shift_registers * 8) {
clock_pin = 0;
if(data_pin) buttons[m] = '0'; else buttons[m] = '1';
clock_pin = 1;
m++;
}
}
 
void main() {
ADCON1 |= 0x0F;
CMCON |= 7;
 
TRISA = 0x00; // define all ports as outputs
TRISA.F3 = 1 ; // data_pin of 74HC165 must be defined as input
PORTA = 0x00; // clear PORTA
 
while(1) {
// Example how to use 74HC595. First four ports has HIGH value and last four has LOW value
write_outputs_595("010101010");
// Example how to read inputs from shift register 74HC165
read_inputs_165(number_of_74hc165s);
 
// Check Button 1
if(buttons[0] == '1') { write_outputs_595("00000001");delay_ms(2000); }
if(buttons[1] == '1') { write_outputs_595("00000010");delay_ms(2000);}
if(buttons[3] == '1') { write_outputs_595("00000100");delay_ms(2000);}
..............
 
// Button 1 is pressed .....
// Do whatever you want ..
 
}
}