Revision 0:d3514bc63a39, committed 2016-01-22

Comitter:

irsanjul

Date:

Fri Jan 22 08:56:27 2016 +0000

Commit message:

Library of Temperature/Humidity Sensor from Silicon Labs for LPC1768; Editing from SILABS_RHT library

Changed in this revision

diff -r 000000000000 -r d3514bc63a39 Si7021.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Si7021.cpp	Fri Jan 22 08:56:27 2016 +0000
@@ -0,0 +1,52 @@
+#include "Si7021.h"
+
+Si7021::Si7021(PinName sda, PinName scl):i2c(sda, scl)
+{
+    i2c.frequency(FREQ);
+}
+
+Si7021::~Si7021()
+{
+    
+}
+
+int32_t Si7021::get_temperature()
+{
+    return tData;
+}
+
+uint32_t Si7021::get_humidity()
+{
+    return rhData;
+}
+
+bool Si7021::measure()
+{
+    tx_buff[0] = READ_RH;
+    if(i2c.write(ADDR, (char*)tx_buff, 1) != 0) return 0;
+    if(i2c.read(ADDR, (char*)rx_buff, 2) != 0) return 0;
+    
+    rhData = ((uint32_t)rx_buff[0] << 8) + (rx_buff[1] & 0xFC);
+    rhData = (((rhData) * 15625L) >> 13) - 6000;
+    
+    tx_buff[0] = READ_TEMP;
+    if(i2c.write(ADDR, (char*)tx_buff, 1) != 0) return 0;
+    if(i2c.read(ADDR, (char*)rx_buff, 2) != 0) return 0;
+    
+    tData = ((uint32_t)rx_buff[0] << 8) + (rx_buff[1] & 0xFC);
+    tData = (((tData) * 21965L) >> 13) - 46850;
+    
+    return 1;
+}
+
+bool Si7021::check()
+{
+    tx_buff[0] = READ_ID2_1;
+    tx_buff[1] = READ_ID2_2;
+    if(i2c.write(ADDR, (char*)tx_buff, 2) != 0) return 0;
+    if(i2c.read(ADDR, (char*)rx_buff, 8) != 0) return 0;
+    
+    if(rx_buff[0] == DEVICE_ID)
+        return true;
+    else return 0;
+}
\ No newline at end of file

diff -r 000000000000 -r d3514bc63a39 Si7021.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Si7021.h	Fri Jan 22 08:56:27 2016 +0000
@@ -0,0 +1,72 @@
+#ifndef SI7021_H
+#define SI7021_H
+
+#include "mbed.h"
+
+/** Si7012 Read Temperature Command */
+#define READ_TEMP        0xE0 /* Read previous T data from RH measurement command*/
+/** Si7012 Read RH Command */
+#define READ_RH          0xE5 /* Perform RH (and T) measurement. */
+
+/** Si7012 Read ID */
+#define READ_ID1_1       0xFA
+#define READ_ID1_2       0x0F
+#define READ_ID2_1       0xFC
+#define READ_ID2_2       0xC9
+
+/** Si7012 Read Firmware Revision */
+#define READ_FWREV_1     0x84
+#define READ_FWREV_2     0xB8
+
+/** I2C device address for Si7021 */
+#define ADDR    0x80
+
+/** I2C device frequency for Si7021 */
+#define FREQ    100000
+
+/** Device ID value for Si7021 */
+#define DEVICE_ID 0x15
+
+class Si7021
+{
+public:
+    Si7021(PinName sda, PinName scl);
+    ~Si7021();
+    
+    /*
+     * Get last measured temperature data
+     * return: int32_t = temperature in millidegrees centigrade
+     */
+    int32_t get_temperature();
+
+    /*
+     * Get last measured relative humidity data
+     * return: uint32_t = relative humidity value in milli-percent
+     */
+    uint32_t get_humidity();
+    
+    /*
+     * Perform measurement.
+     * Asynchronous callback can be provided (type void (*)(void)).
+     * return: 0 if successful, else one of the defined error codes.
+     */
+    bool measure();
+    
+    /*
+     * Check if the sensor is active and responding. This will update the get_active value.
+     * Asynchronous callback can be provided (type void (*)(void)).
+     * return: 0 if successful, else one of the defined error codes.
+     */
+    bool check();
+    
+private:
+    I2C i2c;
+    
+    uint8_t  rx_buff[8];
+    uint8_t  tx_buff[2];
+
+    uint32_t rhData;
+    int32_t  tData;
+};
+
+#endif
\ No newline at end of file