Joseph Ellsworth
Testing SHT75 humidity sensor on STM F303K8 board.
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Nucleo-F303K8-SSD1306_OLED
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Joseph Ellsworth
Sample code to test SHT75 humidity sensor using STM F303K8 board. Uses a 3.3V from board to power sensor. 10K resistor Pull-up on data. Must not be on same pins as I2C. Uses D0 for Clk and D1 for Data.
I had to modify sample code supplied by https://developer.mbed.org/users/nimbusgb/code/SHT75/ because the sensor failed to read without the softReset() and readStatus() at beginning of measurement loop. I think this is caused by the 72Mhtz speed of the F303K8 but did not attempt to fully diagnose.
The readStatus() method from library seems to malfunction and always return a -1 which never changes even when sensor is unplugged.
See https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/Humidity_Sensors/Sensirion_Humidity_Sensors_SHT7x_Datasheet_V5.pdf section 2.1 for wiring.
Diff: main.cpp
- Revision:
- 0:fa185766e039
- Child:
- 1:90d213185462
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Sat Mar 19 02:18:42 2016 +0000
@@ -0,0 +1,52 @@
+/* Example of Reading all the ADC pins available on the Nucleo_F303K8.
+ by Joseph Ellsworth CTO A2WH - Free for all but no warranty, no promises */
+
+#include "mbed.h"
+
+// Initialize a pins to perform analog input and digital output fucntions
+AnalogIn aA7(PA_2);
+AnalogIn aA6(PA_7);
+AnalogIn aA5(PA_6);
+AnalogIn aA4(PA_5);
+AnalogIn aA3(PA_4);
+AnalogIn aA2(PA_3);
+AnalogIn aA1(PA_1);
+AnalogIn aA0(PA_0);
+AnalogIn aB0(PB_0);
+AnalogIn aB1(PB_1);
+
+DigitalOut myled(LED1);
+const float voltMeterARef = 3.3;
+
+float readPrint(AnalogIn ain, char *label) {
+ float tval = ain.read();
+ float volts = tval * voltMeterARef;
+ float perc = tval * 100.0;
+ unsigned short tvalu16 = ain.read_u16 ();
+
+ printf("adc %s R=%3.3f V=%3.3f%% U16=%u\r\n",label, tval, volts, tvalu16);
+
+ return tval;
+}
+
+
+int main() {
+
+ while(1) {
+ myled = !myled; // toggle led
+ readPrint(aA7, "PA_7");
+ readPrint(aA6, "PA_6");
+ readPrint(aA5, "PA_5");
+ readPrint(aA4, "PA_4");
+ readPrint(aA3, "PA_3");
+ readPrint(aA2, "PA_2");
+ readPrint(aA1, "PA_1");
+ readPrint(aA0, "PA_0");
+
+ readPrint(aB0, "PB_0");
+ readPrint(aB1, "PB_1");
+ printf("\r\n\r\n");
+ wait(7.0);
+
+ }
+}