wiringX Hummingboard TMP102 I2C and sparkfun 7-segment display

i2c_spi_test.c

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>

#include "wiringX.h"

/* I2C Config */
#define I2C_ADDR	0x48
#define TMP_WR	 	0x90 //Assume ADR0 is tied to VCC
#define TMP_RD	 	0x91
#define TEMP_REG 	0x00

/* SPI Config */
#define SPI_CHAN	0
#define SPI_SPEED	250000

int fd;
int fd_spi;

void clearDisplaySPI() {
	unsigned char spi_data[1] = {0x76};
	fprintf(stderr, "data = %X\n", spi_data[0]);
	wiringXSPIDataRW(SPI_CHAN, spi_data, 1);  // Clear display command
}
void setCursorSPI() {
	unsigned char spi_data[2] = {0x79, 0x00};
	fprintf(stderr, "data = %X%X\n", spi_data[0], spi_data[1]);
	wiringXSPIDataRW(SPI_CHAN, spi_data, 2);  // set cursor command
}
void setDecimalsSPI(unsigned char decimals) {
	unsigned char spi_data[2] = {0x77, decimals};
	fprintf(stderr, "data = %X%X\n", spi_data[0], spi_data[1]);
	wiringXSPIDataRW(SPI_CHAN, spi_data, 2);
}

int main(void) {
	wiringXSetup();
	if ((fd = wiringXI2CSetup(I2C_ADDR)) < 0 ) {
		fprintf(stderr, "I2C Setup failed: %i\n", fd);
		return -1;
	} else {
		fprintf(stderr, "I2C Setup OK: %i\n", fd);
	}
	char reg[2] = {0,0};
	int data = 0;
	unsigned char spi_data[4] = "0000";
	char temp_str[5];

	pinMode(1, OUTPUT);
	if ((fd_spi = wiringXSPISetup(SPI_CHAN, SPI_SPEED)) < 0) {
		fprintf(stderr, "SPI Setup failed: %i\n", fd_spi);
	} else {
		fprintf(stderr, "SPI Setup OK: %i\n", fd_spi);
	}
	clearDisplaySPI();
	while(1) {
		digitalWrite(1, HIGH);
		data = wiringXI2CReadReg16(fd, TEMP_REG);
		//fprintf(stderr, "data = 0x%0*x\n", 4, data);
		reg[0] = (data>>8)&0xff;
		reg[1] = data&0xff;
		//fprintf(stderr, "msb = %i\n", reg[1]);
		//fprintf(stderr, "lsb = %i\n", reg[0]);
		int16_t res  = ((int8_t)reg[1] << 4) | ((uint8_t)reg[0] >> 4);
		float temp =  (float) ((float)res * 0.0625);
		fprintf(stderr, "temp = %2.2f\n", temp);
		sprintf(temp_str, "%2.2f", temp);
		spi_data[0] = (temp_str[0] - '0') & 0xff;
		spi_data[1] = (temp_str[1] - '0') & 0xff;
		spi_data[2] = (temp_str[3] - '0') & 0xff;
		spi_data[3] = (temp_str[4] - '0') & 0xff;
		fprintf(stderr, "data = %X%X%X%X\n", spi_data[0], spi_data[1], spi_data[2], spi_data[3]);
		setCursorSPI();
		wiringXSPIDataRW(SPI_CHAN, spi_data, 4);
		setDecimalsSPI(2&0xff);
		sleep(2);
		digitalWrite(1, LOW);
		sleep(2);
	}
}