#include <xc.h>
#pragma config FOSC = HSMP // HS oscillator - medium power
#pragma config PWRTEN = ON // Powerup timer on
#pragma config BOREN = OFF // Brownout detect off
#pragma config LVP = OFF // Low voltage programming off
#pragma config PBADEN = OFF // Port B all digital I/O
#define _XTAL_FREQ 4000000 // Clock frequency for delay functions
// Port definitions
#define TRIS_SDI TRISCbits.TRISC5 // Direction define SDI input
#define TRIS_SCK TRISCbits.TRISC3 // Direction define clock pin as output
#define CS PORTBbits.RB0 // CS - RB0
#define TRIS_CS TRISBbits.TRISB0 // Direction CS - B0
#define TRIS_SDO TRISCbits.TRISC4// Direction SD0 as output
// MCP23S08 registers taken from datasheet
#define mcp23S08_read 0x47 // Control byte 01000 - first 5 bits. 11 A1 A0 - user dependent - last bit R/W=1 so read
#define mcp23S08_address_write 0x46 // Control byte 01000 - 11(A1 A0), R/W=0 so write
#define MCP_IODIR 0x00 // IO Direction register set to output
#define MCP_IPOL 0x01 // IO Polarity register - bit7 opposite logic state of the input pin
#define MCP_IOCON 0x05 // bit 0=1 - but unimplemented in data sheet. bit 2=1 - overrides intpol
#define MCP_GPPU 0x06 // 00000110 - pull-up resistor enabled on bit 1&2
#define MCP_GPIO 0x09 //
#define MCP_DEFVAL 0x03
#define MCP_INTCON 0x04
// LCD definitions
#define LCD_Port PORTB
#define EN PORTCbits.RC6
#define RS PORTCbits.RC7
#define Set_LCD_Address_command 0x80
#define Set_LCD_Position_R1C1 0x00
#define Set_LCD_Position_R2C1 0xC0
#define clear_LCD 0x01
// Function declarations
void PIC_Initialise(void);
void SPI_Initiailise(void);
void MCP23S08_Initialise(void);
void SPI_Send_data(unsigned char device_address, unsigned char register_adress, unsigned char register_data);
void WriteSPI(unsigned char data);
unsigned char ReadDipswitches(void);
void LCD_Init(void);
void LCD_Command(unsigned char cmd);
void LCD_Char(char dat);
void LCD_String(char *msg);
void main(void) {
PIC_Initialise();
SPI_Initiailise();
MCP23S08_Initialise();
LCD_Init();
LCD_Command(0x80);
LCD_String("Crying");
__delay_ms(1000);
LCD_Command(clear_LCD);
while (1) {
unsigned char switchState = ReadDipswitches();
LCD_Command(0x80); // Move cursor to the beginning of the first line
LCD_String("DIPSWITCH: ");
LCD_Char(switchState + '0'); // Display the switch state as a character
__delay_ms(500); // Delay before checking the dipswitches again
}
}
void PIC_Initialise(void) {
// Configure SPI pins
TRISCbits.TRISC3 = 0; // SCK as output
TRISCbits.TRISC4 = 1; // SDI as input
TRISCbits.TRISC5 = 0; // SDO as output
TRISBbits.TRISB0 = 0; // CS as output
// Configure LCD control pins
TRISCbits.TRISC6 = 0; // EN as output
TRISCbits.TRISC7 = 0; // RS as output
// Configure LCD data pins
TRISBbits.TRISB4 = 0; // Data 4 as output
TRISBbits.TRISB5 = 0; // Data 5 as output
TRISBbits.TRISB6 = 0; // Data 6 as output
TRISBbits.TRISB7 = 0; // Data 7 as output
// Set all other ports as digital outputs
ANSELA = ANSELB = ANSELC = 0x00;
// Clear all port outputs
LATA = LATB = LATC = 0x00;
}
void SPI_Initiailise(void) {
SSP1STAT = 0x40; // Bit 6 set to 1 - SPI Clock Edge Select
SSP1CON1 = 0x20; // Enables serial port and configures SCKx, SDOx, SDIx and SSx, clock = FOSC / 4
}
void MCP23S08_Initialise ()
{
SPI_Send_data(mcp23S08_address_write, MCP_IOCON, 0x38); //sequential and slew disables
SPI_Send_data(mcp23S08_address_write, MCP_IODIR, 0xFF); // sets all as inputs
SPI_Send_data(mcp23S08_address_write, MCP_IPOL, 0x00); //set polarity to same
SPI_Send_data(mcp23S08_address_write, MCP_GPPU, 0x00); //pull ups disabled
SPI_Send_data(mcp23S08_address_write, MCP_INTCON, 0x00); //compare register for interrupt on change
SPI_Send_data(mcp23S08_address_write, MCP_DEFVAL, 0x00); //compare register for interrupt on change
}
void SPI_Send_data(unsigned char device_address, unsigned char register_adress, unsigned char register_data) {
CS = 0;
WriteSPI(device_address);
WriteSPI(register_adress);
WriteSPI(register_data);
CS = 1;
}
void WriteSPI(unsigned char data) {
SSP1BUF = data; // Write data to SSPBUF (data buffer)
while(!PIR1bits.SSPIF); // Wait for complete 1 byte transmission
PIR1bits.SSPIF = 0; // Clear SSPIF flag
}
unsigned char ReadDipswitches(void) {
unsigned char switchState;
CS = 0; // Lower chip select line
WriteSPI(mcp23S08_read); // Selecting read address
WriteSPI(MCP_GPIO); // GPIO register selection
// Dummy write to receive data
SSP1BUF = 0x00;
while(!SSP1STATbits.BF); // Wait for buffer full
switchState = SSP1BUF; // Read received data
CS = 1;
return switchState; // Value read from SSP1BUF (data buffer) is the SPI
}
void LCD_Init(void)
{
LCD_Port = 0x00; // Port as output port
__delay_ms(20); // 41ms delay
LCD_Command(0x30); //
__delay_ms(5); // 41ms delay
LCD_Command(0x30); //
__delay_ms(2); // 41ms delay
LCD_Command(0x30); //
__delay_ms(1); // 41ms delay
LCD_Command(0x02); // Return home
__delay_ms(5); // 41ms delay
LCD_Command(0x28); //
__delay_ms(5); // 1ms delay
LCD_Command(0x08); //
__delay_ms(5); // 1ms delay
LCD_Command(0x01); // Clear Display
__delay_ms(15); // 41ms delay
LCD_Command(0x06); //
__delay_ms(1); // 2ms delay
LCD_Command(0x0F); //
__delay_ms(1); // 2ms delay
}
void LCD_Command(unsigned char cmd)
{
char ldata = 0;
ldata = (ldata & 0x0f) | (0xF0 & cmd); //
RS = 0; //
EN = 1; //
PORTB = ldata;
__delay_ms(1);
EN = 0;
__delay_ms(5);
ldata = (ldata & 0x0f) | (cmd << 4); //
PORTB = ldata;
EN = 1;
__delay_ms(1);
EN = 0;
__delay_ms(5);
}
void LCD_String(char *msg)
{
while ((*msg) != 0)
{
LCD_Char(*msg);
msg++;
}
}
void LCD_Char(char dat)
{
char ldata = 0;
ldata = (ldata & 0x0f) | (0xF0 & dat);
//ldata = dat; //
PORTB = ldata;
RS = 1; //
EN = 1; //
// NOP();
__delay_us(10);
EN = 0;
__delay_ms(5);
ldata = (ldata & 0x0f) | (dat << 4);
//ldata = dat; //
PORTB = ldata;
EN = 1; //High
__delay_us(10);
// NOP();
EN = 0;
__delay_ms(5);
}