Serge Sozonoff
Port of the SHT2x example code from Sensirion
Dependents: sht21_test ENVLogger
Diff: SHT2x.cpp
- Revision:
- 1:d0f691423bf1
- Parent:
- 0:74df6ab91c79
- Child:
- 2:2464fed17980
--- a/SHT2x.cpp Sat Apr 23 14:08:11 2011 +0000
+++ b/SHT2x.cpp Sat Apr 23 18:10:56 2011 +0000
@@ -10,11 +10,9 @@
//==============================================================================//
//---------- Includes ----------------------------------------------------------
#include "SHT2x.h"
+#include "mbed.h"
-SHT2x::SHT2x (PinName p_sda, PinName p_scl) : i2c(p_sda, p_scl) {
-}
-
-SHT2x::SHT2x (I2C& p_i2c) : i2c(p_i2c) {
+SHT2x::SHT2x (PinName p_sda, PinName p_scl) : i2c(p_sda, p_scl), out(USBTX, USBRX) {
}
//==============================================================================//
@@ -40,19 +38,19 @@
{
int checksum; //variable for checksum byte
int error=0; //variable for error code
-
+
i2c.start();
i2c.write(I2C_ADR_W);
i2c.write(USER_REG_R);
-
+
i2c.start();
i2c.write(I2C_ADR_R);
-
-
- *pRegisterValue = i2c.read(1);
-
- checksum=i2c.read(0);
-
+
+
+ *pRegisterValue = i2c.read(ACK);
+
+ checksum=i2c.read(NoACK);
+
error |= SHT2x_CheckCrc (pRegisterValue,1,checksum);
i2c.stop();
@@ -64,7 +62,7 @@
{
int error=0; //variable for error code
i2c.start();
-
+
i2c.write(I2C_ADR_W);
i2c.write(USER_REG_W);
i2c.write(*pRegisterValue);
@@ -79,43 +77,48 @@
int checksum; //checksum
int data[2]; //data array for checksum verification
int error=0; //error variable
-
- //-- write I2C sensor address and command --
+ int i;
+
+ //-- write I2C sensor address and command --
i2c.start();
-
+
i2c.write(I2C_ADR_W); // I2C Adr
switch (eSHT2xMeasureType) {
case HUMIDITY:
i2c.write(TRIG_RH_MEASUREMENT_HM);
break;
- case TEMP :
+ case TEMP:
i2c.write(TRIG_T_MEASUREMENT_HM);
break;
default:
break;
}
+
//-- wait until hold master is released --
- i2c.start();
+ i2c.start();
i2c.write(I2C_ADR_R);
-
+
//SCL=HIGH; // set SCL I/O port as input
-
- //for (i=0; i<1000; i++) { // wait until master hold is released or
- // DelayMicroSeconds(1000); // a timeout (~1s) is reached
- // if (SCL_CONF==1) break;
- //}
-
+ i2c.sclAsInput();
+
+ for (i=0; i<1000; i++) { // wait until master hold is released or
+ wait_ms(1); // a timeout (~1s) is reached
+ if (i2c.sclRead() == 1) break;
+ }
+
//-- check for timeout --
- //if (SCL_CONF==0) error |= TIME_OUT_ERROR;
-//-- read two data bytes and one checksum byte --
+ if (i2c.sclRead() == 0) error |= TIME_OUT_ERROR;
+ //-- read two data bytes and one checksum byte --
- data[0] = i2c.read(1);
- data[1] = i2c.read(1);
-
+ i2c.sclNormal();
+
+ data[0] = i2c.read(ACK);
+ data[1] = i2c.read(ACK);
+
*pMeasurand = data[0] << 8;
*pMeasurand |= data[1];
-
- checksum = i2c.read(0);
+
+ checksum = i2c.read(NoACK);
//-- verify checksum --
error |= SHT2x_CheckCrc (data, 2, checksum);
@@ -133,7 +136,7 @@
//-- write I2C sensor address and command --
i2c.start();
-
+
i2c.write(I2C_ADR_W);
switch (eSHT2xMeasureType) {
case HUMIDITY:
@@ -144,25 +147,25 @@
break;
default:
break;
-
+
}
//-- poll every 10ms for measurement ready. Timeout after 20 retries (200ms)--
do {
i2c.start();
- wait_ms(10);
+ wait_ms(10);
if (i++ >= 20) break;
} while (i2c.write(I2C_ADR_R) == 0);
-
+
if (i >= 20) error |= TIME_OUT_ERROR;
-
+
//-- read two data bytes and one checksum byte --
- data[0] = i2c.read(1);
- data[1] = i2c.read(1);
-
+ data[0] = i2c.read(ACK);
+ data[1] = i2c.read(ACK);
+
*pMeasurand = data[0] << 8;
- *pMeasurand |= data[1];
-
- checksum = i2c.read(0);
+ *pMeasurand |= data[1];
+
+ checksum = i2c.read(NoACK);
//-- verify checksum --
error |= SHT2x_CheckCrc (data,2,checksum);
i2c.stop();
@@ -196,7 +199,7 @@
{
float temperatureC; // variable for result
u16sT &= ~0x0003; // clear bits [1..0] (status bits)
- //-- calculate temperature [°C] --
+ //-- calculate temperature [�C] --
temperatureC= -46.85 + 175.72/65536 *(float)u16sT; //T= -46.85 + 175.72 * ST/2^16
return temperatureC;
}
@@ -205,21 +208,21 @@
//==============================================================================//
{
int error=0; //error variable
- //Read from memory location 1
+ //Read from memory location 1
i2c.start();
- error |= i2c.write(I2C_ADR_W);
+ error |= i2c.write(I2C_ADR_W);
error |= i2c.write(0xFA); //Command for readout on-chip memory
error |= i2c.write(0x0F); //on-chip memory address
i2c.start();
error |= i2c.write(I2C_ADR_R); //I2C address
- u8SerialNumber[5] = i2c.read(1); //Read SNB_3
- i2c.read(1); //Read CRC SNB_3 (CRC is not analyzed)
- u8SerialNumber[4] = i2c.read(1); //Read SNB_2
- i2c.read(1); //Read CRC SNB_2 (CRC is not analyzed)
- u8SerialNumber[3] = i2c.read(1); //Read SNB_1Sample Code SHT21
- i2c.read(1); //Read CRC SNB_1 (CRC is not analyzed)
- u8SerialNumber[2] = i2c.read(1); //Read SNB_0
- i2c.read(0); //Read CRC SNB_0 (CRC is not analyzed)
+ u8SerialNumber[5] = i2c.read(ACK); //Read SNB_3
+ i2c.read(ACK); //Read CRC SNB_3 (CRC is not analyzed)
+ u8SerialNumber[4] = i2c.read(ACK); //Read SNB_2
+ i2c.read(ACK); //Read CRC SNB_2 (CRC is not analyzed)
+ u8SerialNumber[3] = i2c.read(ACK); //Read SNB_1Sample Code SHT21
+ i2c.read(ACK); //Read CRC SNB_1 (CRC is not analyzed)
+ u8SerialNumber[2] = i2c.read(ACK); //Read SNB_0
+ i2c.read(NoACK); //Read CRC SNB_0 (CRC is not analyzed)
i2c.stop();
//Read from memory location 2
i2c.start();
@@ -228,12 +231,12 @@
error |= i2c.write(0xC9); //on-chip memory address
i2c.start();
error |= i2c.write(I2C_ADR_R); //I2C address
- u8SerialNumber[1] = i2c.read(1); //Read SNC_1
- u8SerialNumber[0] = i2c.read(1); //Read SNC_0
- i2c.read(1);
- u8SerialNumber[7] = i2c.read(1); //Read SNA_1
- u8SerialNumber[6] = i2c.read(1); //Read SNA_0
- i2c.read(0); //Read CRC SNA0/1 (CRC is not analyzed)
+ u8SerialNumber[1] = i2c.read(ACK); //Read SNC_1
+ u8SerialNumber[0] = i2c.read(ACK); //Read SNC_0
+ i2c.read(ACK);
+ u8SerialNumber[7] = i2c.read(ACK); //Read SNA_1
+ u8SerialNumber[6] = i2c.read(ACK); //Read SNA_0
+ i2c.read(NoACK); //Read CRC SNA0/1 (CRC is not analyzed)
i2c.stop();
return error;
}
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