main.c

/*
 * I2C Example project for the mcb32 toolchain
 * Demonstrates the temperature sensor and display of the Basic IO Shield
 * Make sure your Uno32-board has the correct jumper settings, as can be seen
 * in the rightmost part of this picture:
 * https://reference.digilentinc.com/_media/chipkit_uno32:jp6_jp8.png?w=300&tok=dcceb2
 */

#include <pic32mx.h>
#include <stdint.h>
#include <stdbool.h>

#define DISPLAY_VDD_PORT PORTF
#define DISPLAY_VDD_MASK 0x40
#define DISPLAY_VBATT_PORT PORTF
#define DISPLAY_VBATT_MASK 0x20
#define DISPLAY_COMMAND_DATA_PORT PORTF
#define DISPLAY_COMMAND_DATA_MASK 0x10
#define DISPLAY_RESET_PORT PORTG
#define DISPLAY_RESET_MASK 0x200

/* Address of the temperature sensor on the I2C bus */
#define TEMP_SENSOR_ADDR 0x48

/* Temperature sensor internal registers */
typedef enum TempSensorReg TempSensorReg;
enum TempSensorReg {
	TEMP_SENSOR_REG_TEMP,
	TEMP_SENSOR_REG_CONF,
	TEMP_SENSOR_REG_HYST,
	TEMP_SENSOR_REG_LIMIT,
};


char textbuffer[4][16];

static const uint8_t const font[] = {
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 2, 5, 2, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 94, 0, 0, 0, 0,
	0, 0, 4, 3, 4, 3, 0, 0,
	0, 36, 126, 36, 36, 126, 36, 0,
	0, 36, 74, 255, 82, 36, 0, 0,
	0, 70, 38, 16, 8, 100, 98, 0,
	0, 52, 74, 74, 52, 32, 80, 0,
	0, 0, 0, 4, 3, 0, 0, 0,
	0, 0, 0, 126, 129, 0, 0, 0,
	0, 0, 0, 129, 126, 0, 0, 0,
	0, 42, 28, 62, 28, 42, 0, 0,
	0, 8, 8, 62, 8, 8, 0, 0,
	0, 0, 0, 128, 96, 0, 0, 0,
	0, 8, 8, 8, 8, 8, 0, 0,
	0, 0, 0, 0, 96, 0, 0, 0,
	0, 64, 32, 16, 8, 4, 2, 0,
	0, 62, 65, 73, 65, 62, 0, 0,
	0, 0, 66, 127, 64, 0, 0, 0,
	0, 0, 98, 81, 73, 70, 0, 0,
	0, 0, 34, 73, 73, 54, 0, 0,
	0, 0, 14, 8, 127, 8, 0, 0,
	0, 0, 35, 69, 69, 57, 0, 0,
	0, 0, 62, 73, 73, 50, 0, 0,
	0, 0, 1, 97, 25, 7, 0, 0,
	0, 0, 54, 73, 73, 54, 0, 0,
	0, 0, 6, 9, 9, 126, 0, 0,
	0, 0, 0, 102, 0, 0, 0, 0,
	0, 0, 128, 102, 0, 0, 0, 0,
	0, 0, 8, 20, 34, 65, 0, 0,
	0, 0, 20, 20, 20, 20, 0, 0,
	0, 0, 65, 34, 20, 8, 0, 0,
	0, 2, 1, 81, 9, 6, 0, 0,
	0, 28, 34, 89, 89, 82, 12, 0,
	0, 0, 126, 9, 9, 126, 0, 0,
	0, 0, 127, 73, 73, 54, 0, 0,
	0, 0, 62, 65, 65, 34, 0, 0,
	0, 0, 127, 65, 65, 62, 0, 0,
	0, 0, 127, 73, 73, 65, 0, 0,
	0, 0, 127, 9, 9, 1, 0, 0,
	0, 0, 62, 65, 81, 50, 0, 0,
	0, 0, 127, 8, 8, 127, 0, 0,
	0, 0, 65, 127, 65, 0, 0, 0,
	0, 0, 32, 64, 64, 63, 0, 0,
	0, 0, 127, 8, 20, 99, 0, 0,
	0, 0, 127, 64, 64, 64, 0, 0,
	0, 127, 2, 4, 2, 127, 0, 0,
	0, 127, 6, 8, 48, 127, 0, 0,
	0, 0, 62, 65, 65, 62, 0, 0,
	0, 0, 127, 9, 9, 6, 0, 0,
	0, 0, 62, 65, 97, 126, 64, 0,
	0, 0, 127, 9, 9, 118, 0, 0,
	0, 0, 38, 73, 73, 50, 0, 0,
	0, 1, 1, 127, 1, 1, 0, 0,
	0, 0, 63, 64, 64, 63, 0, 0,
	0, 31, 32, 64, 32, 31, 0, 0,
	0, 63, 64, 48, 64, 63, 0, 0,
	0, 0, 119, 8, 8, 119, 0, 0,
	0, 3, 4, 120, 4, 3, 0, 0,
	0, 0, 113, 73, 73, 71, 0, 0,
	0, 0, 127, 65, 65, 0, 0, 0,
	0, 2, 4, 8, 16, 32, 64, 0,
	0, 0, 0, 65, 65, 127, 0, 0,
	0, 4, 2, 1, 2, 4, 0, 0,
	0, 64, 64, 64, 64, 64, 64, 0,
	0, 0, 1, 2, 4, 0, 0, 0,
	0, 0, 48, 72, 40, 120, 0, 0,
	0, 0, 127, 72, 72, 48, 0, 0,
	0, 0, 48, 72, 72, 0, 0, 0,
	0, 0, 48, 72, 72, 127, 0, 0,
	0, 0, 48, 88, 88, 16, 0, 0,
	0, 0, 126, 9, 1, 2, 0, 0,
	0, 0, 80, 152, 152, 112, 0, 0,
	0, 0, 127, 8, 8, 112, 0, 0,
	0, 0, 0, 122, 0, 0, 0, 0,
	0, 0, 64, 128, 128, 122, 0, 0,
	0, 0, 127, 16, 40, 72, 0, 0,
	0, 0, 0, 127, 0, 0, 0, 0,
	0, 120, 8, 16, 8, 112, 0, 0,
	0, 0, 120, 8, 8, 112, 0, 0,
	0, 0, 48, 72, 72, 48, 0, 0,
	0, 0, 248, 40, 40, 16, 0, 0,
	0, 0, 16, 40, 40, 248, 0, 0,
	0, 0, 112, 8, 8, 16, 0, 0,
	0, 0, 72, 84, 84, 36, 0, 0,
	0, 0, 8, 60, 72, 32, 0, 0,
	0, 0, 56, 64, 32, 120, 0, 0,
	0, 0, 56, 64, 56, 0, 0, 0,
	0, 56, 64, 32, 64, 56, 0, 0,
	0, 0, 72, 48, 48, 72, 0, 0,
	0, 0, 24, 160, 160, 120, 0, 0,
	0, 0, 100, 84, 84, 76, 0, 0,
	0, 0, 8, 28, 34, 65, 0, 0,
	0, 0, 0, 126, 0, 0, 0, 0,
	0, 0, 65, 34, 28, 8, 0, 0,
	0, 0, 4, 2, 4, 2, 0, 0,
	0, 120, 68, 66, 68, 120, 0, 0,
};

void delay(int cyc) {
	int i;
	for(i = cyc; i > 0; i--);
}

uint8_t spi_send_recv(uint8_t data) {
	while(!(SPI2STAT & 0x08));
	SPI2BUF = data;
	while(!(SPI2STAT & 0x01));
	return SPI2BUF;
}

void display_init() {
	DISPLAY_COMMAND_DATA_PORT &= ~DISPLAY_COMMAND_DATA_MASK;
	delay(10);
	DISPLAY_VDD_PORT &= ~DISPLAY_VDD_MASK;
	delay(1000000);
	
	spi_send_recv(0xAE);
	DISPLAY_RESET_PORT &= ~DISPLAY_RESET_MASK;
	delay(10);
	DISPLAY_RESET_PORT |= DISPLAY_RESET_MASK;
	delay(10);
	
	spi_send_recv(0x8D);
	spi_send_recv(0x14);
	
	spi_send_recv(0xD9);
	spi_send_recv(0xF1);
	
	DISPLAY_VBATT_PORT &= ~DISPLAY_VBATT_MASK;
	delay(10000000);
	
	spi_send_recv(0xA1);
	spi_send_recv(0xC8);
	
	spi_send_recv(0xDA);
	spi_send_recv(0x20);
	
	spi_send_recv(0xAF);
}

void display_string(int line, char *s) {
	int i;
	if(line < 0 || line >= 4)
		return;
	if(!s)
		return;
	
	for(i = 0; i < 16; i++)
		if(*s) {
			textbuffer[line][i] = *s;
			s++;
		} else
			textbuffer[line][i] = ' ';
}

void display_update() {
	int i, j, k;
	int c;
	for(i = 0; i < 4; i++) {
		DISPLAY_COMMAND_DATA_PORT &= ~DISPLAY_COMMAND_DATA_MASK;
		spi_send_recv(0x22);
		spi_send_recv(i);
		
		spi_send_recv(0x0);
		spi_send_recv(0x10);
		
		DISPLAY_COMMAND_DATA_PORT |= DISPLAY_COMMAND_DATA_MASK;
		
		for(j = 0; j < 16; j++) {
			c = textbuffer[i][j];
			if(c & 0x80)
				continue;
			
			for(k = 0; k < 8; k++)
				spi_send_recv(font[c*8 + k]);
		}
	}
}

/* Wait for I2C bus to become idle */
void i2c_idle() {
	while(I2C1CON & 0x1F || I2C1STAT & (1 << 14)); //TRSTAT
}

/* Send one byte on I2C bus, return ack/nack status of transaction */
bool i2c_send(uint8_t data) {
	i2c_idle();
	I2C1TRN = data;
	i2c_idle();
	return !(I2C1STAT & (1 << 15)); //ACKSTAT
}

/* Receive one byte from I2C bus */
uint8_t i2c_recv() {
	i2c_idle();
	I2C1CONSET = 1 << 3; //RCEN = 1
	i2c_idle();
	I2C1STATCLR = 1 << 6; //I2COV = 0
	return I2C1RCV;
}

/* Send acknowledge conditon on the bus */
void i2c_ack() {
	i2c_idle();
	I2C1CONCLR = 1 << 5; //ACKDT = 0
	I2C1CONSET = 1 << 4; //ACKEN = 1
}

/* Send not-acknowledge conditon on the bus */
void i2c_nack() {
	i2c_idle();
	I2C1CONSET = 1 << 5; //ACKDT = 1
	I2C1CONSET = 1 << 4; //ACKEN = 1
}

/* Send start conditon on the bus */
void i2c_start() {
	i2c_idle();
	I2C1CONSET = 1 << 0; //SEN
	i2c_idle();
}

/* Send restart conditon on the bus */
void i2c_restart() {
	i2c_idle();
	I2C1CONSET = 1 << 1; //RSEN
	i2c_idle();
}

/* Send stop conditon on the bus */
void i2c_stop() {
	i2c_idle();
	I2C1CONSET = 1 << 2; //PEN
	i2c_idle();
}

/* Convert 8.8 bit fixed point to string representation*/
char *fixed_to_string(uint16_t num, char *buf) {
	bool neg = false;
	uint32_t n;
	char *tmp;
	
	if(num & 0x8000) {
		num = ~num + 1;
		neg = true;
	}
	
	buf += 4;
	n = num >> 8;
	tmp = buf;
	do {
		*--tmp = (n  % 10) + '0';
		n /= 10;
	} while(n);
	if(neg)
		*--tmp = '-';
	
	n = num;
	if(!(n & 0xFF)) {
		*buf = 0;
		return tmp;
	}
	*buf++ = '.';
	while((n &= 0xFF)) {
		n *= 10;
		*buf++ = (n >> 8) + '0';
	}
	*buf = 0;
	
	return tmp;
}

uint32_t strlen(char *str) {
	uint32_t n = 0;
	while(*str++)
		n++;
	return n;
}

int main(void) {
	uint16_t temp;
	char buf[32], *s, *t;

	/* Set up peripheral bus clock */
	OSCCON &= ~0x180000;
	OSCCON |= 0x080000;
	
	/* Set up output pins */
	AD1PCFG = 0xFFFF;
	ODCE = 0x0;
	TRISECLR = 0xFF;
	PORTE = 0x0;
	
	/* Output pins for display signals */
	PORTF = 0xFFFF;
	PORTG = (1 << 9);
	ODCF = 0x0;
	ODCG = 0x0;
	TRISFCLR = 0x70;
	TRISGCLR = 0x200;
	
	/* Set up input pins */
	TRISDSET = (1 << 8);
	TRISFSET = (1 << 1);
	
	/* Set up SPI as master */
	SPI2CON = 0;
	SPI2BRG = 4;
	
	/* Clear SPIROV*/
	SPI2STATCLR &= ~0x40;
	/* Set CKP = 1, MSTEN = 1; */
        SPI2CON |= 0x60;
	
	/* Turn on SPI */
	SPI2CONSET = 0x8000;
	
	/* Set up i2c */
	I2C1CON = 0x0;
	/* I2C Baud rate should be less than 400 kHz, is generated by dividing
	the 40 MHz peripheral bus clock down */
	I2C1BRG = 0x0C2;
	I2C1STAT = 0x0;
	I2C1CONSET = 1 << 13; //SIDL = 1
	I2C1CONSET = 1 << 15; // ON = 1
	temp = I2C1RCV; //Clear receive buffer
	
	/* Set up input pins */
	TRISDSET = (1 << 8);
	TRISFSET = (1 << 1);
	
	
	display_init();
	display_string(0, "Temperature:");
	display_string(1, "");
	display_string(2, "");
	display_string(3, "");
	display_update();
	
	/* Send start condition and address of the temperature sensor with
	write mode (lowest bit = 0) until the temperature sensor sends
	acknowledge condition */
	do {
		i2c_start();
	} while(!i2c_send(TEMP_SENSOR_ADDR << 1));
	/* Send register number we want to access */
	i2c_send(TEMP_SENSOR_REG_CONF);
	/* Set the config register to 0 */
	i2c_send(0x0);
	/* Send stop condition */
	i2c_stop();
	
	for(;;) {
		/* Send start condition and address of the temperature sensor with
		write flag (lowest bit = 0) until the temperature sensor sends
		acknowledge condition */
		do {
			i2c_start();
		} while(!i2c_send(TEMP_SENSOR_ADDR << 1));
		/* Send register number we want to access */
		i2c_send(TEMP_SENSOR_REG_TEMP);
		
		/* Now send another start condition and address of the temperature sensor with
		read mode (lowest bit = 1) until the temperature sensor sends
		acknowledge condition */
		do {
			i2c_start();
		} while(!i2c_send((TEMP_SENSOR_ADDR << 1) | 1));
		
		/* Now we can start receiving data from the sensor data register */
		temp = i2c_recv() << 8;
		i2c_ack();
		temp |= i2c_recv();
		/* To stop receiving, send nack and stop */
		i2c_nack();
		i2c_stop();
		
		s = fixed_to_string(temp, buf);
		t = s + strlen(s);
		*t++ = ' ';
		*t++ = 7;
		*t++ = 'C';
		*t++ = 0;
		
		display_string(1, s);
		display_update();
		delay(1000000);
	}
	
	return 0;
}