From e2f0937f9c73f2c3a731915208b988aa2090e308 Mon Sep 17 00:00:00 2001
From: Gerardo Marx <gmarx_cc@itmorelia.edu.mx>
Date: Thu, 8 Oct 2026 11:00:28 -0600
Subject: [PATCH] testing temperature function

---
 htu21d.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
 htu21d.h |  2 ++
 main.c   | 27 +++++++++++++++++++++++++++
 3 files changed, 73 insertions(+)
 create mode 100644 htu21d.c
 create mode 100644 main.c

diff --git a/htu21d.c b/htu21d.c
new file mode 100644
index 0000000..3dda8a3
--- /dev/null
+++ b/htu21d.c
@@ -0,0 +1,44 @@
+#include <unistd.h> //i2c
+#include <sys/ioctl.h>
+#include <linux/i2c-dev.h>
+#include <i2c/smbus.h>
+#include <stdio.h>
+
+#include "htu21d.h"
+
+// i2cReset
+int i2cReset(int fd){
+	if(ioctl(fd, I2C_SLAVE, ADDR)<0){
+		perror("Failed to open the I2C bus: reset\n");
+		return -1;
+	}
+	i2c_smbus_write_byte(fd, RESET);
+	return 0;
+}
+
+// get temp
+int getTemp(int fd, double *temp){
+	char buffer[3];
+	int response = i2c_smbus_read_i2c_block_data(fd, TEMP,3,buffer);
+	if(response<0){
+		perror("Failed to read temperature from sensor\n");
+		return -1;
+	}
+	*temp = -46.85+175.72*(buffer[0]*256+buffer[1])/65536;
+	return 0;
+}
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+// get humidity
diff --git a/htu21d.h b/htu21d.h
index 7e08668..ff73173 100644
--- a/htu21d.h
+++ b/htu21d.h
@@ -12,6 +12,8 @@
 #define RESET 0xFE
 
 // prototype functions:
+int i2cReset(int fd);
+
 int getTemp(int fd, double *temp);
 
 int getHum(int fd, double *hum);
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..1ab1f52
--- /dev/null
+++ b/main.c
@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "htu21d.h"
+
+int main(int argc, char *argv[]){
+	int fd;
+	char path[20];
+	snprintf(path, sizeof(path), "/dev/i2c-%d", 1);
+	fd = open(path, O_RDWR);
+	if(fd<0){
+		//printf("Error");
+		perror("Unable to access the i2c bus path\n");
+		return -1;
+	}
+	i2cReset(fd);
+	double temperature;
+	int status = getTemp(fd, &temperature);
+	if(status<0){
+		perror("Unable to get temperature\n");
+		return -1;
+	}
+	printf("%5.2f C\n", temperature);
+	return 0;
+}