Joseph Ellsworth / Mbed 2 deprecated xj-Nucleo-F303K8-SHT75-TEST

Testing SHT75 humidity sensor on STM F303K8 board.

Dependencies:   SHT75 mbed

Fork of Nucleo-F303K8-SSD1306_OLED by 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.

main.cpp@0:fa185766e039, 2016-03-19 (annotated)

Committer:
joeata2wh
Date:
Sat Mar 19 02:18:42 2016 +0000
Revision:
0:fa185766e039
Child:
1:90d213185462
working version

Who changed what in which revision?

UserRevisionLine numberNew contents of line
joeata2wh 0:fa185766e039 1 /* Example of Reading all the ADC pins available on the Nucleo_F303K8.
joeata2wh 0:fa185766e039 2 by Joseph Ellsworth CTO A2WH - Free for all but no warranty, no promises */
joeata2wh 0:fa185766e039 3
joeata2wh 0:fa185766e039 4 #include "mbed.h"
joeata2wh 0:fa185766e039 5
joeata2wh 0:fa185766e039 6 // Initialize a pins to perform analog input and digital output fucntions
joeata2wh 0:fa185766e039 7 AnalogIn aA7(PA_2);
joeata2wh 0:fa185766e039 8 AnalogIn aA6(PA_7);
joeata2wh 0:fa185766e039 9 AnalogIn aA5(PA_6);
joeata2wh 0:fa185766e039 10 AnalogIn aA4(PA_5);
joeata2wh 0:fa185766e039 11 AnalogIn aA3(PA_4);
joeata2wh 0:fa185766e039 12 AnalogIn aA2(PA_3);
joeata2wh 0:fa185766e039 13 AnalogIn aA1(PA_1);
joeata2wh 0:fa185766e039 14 AnalogIn aA0(PA_0);
joeata2wh 0:fa185766e039 15 AnalogIn aB0(PB_0);
joeata2wh 0:fa185766e039 16 AnalogIn aB1(PB_1);
joeata2wh 0:fa185766e039 17
joeata2wh 0:fa185766e039 18 DigitalOut myled(LED1);
joeata2wh 0:fa185766e039 19 const float voltMeterARef = 3.3;
joeata2wh 0:fa185766e039 20
joeata2wh 0:fa185766e039 21 float readPrint(AnalogIn ain, char *label) {
joeata2wh 0:fa185766e039 22 float tval = ain.read();
joeata2wh 0:fa185766e039 23 float volts = tval * voltMeterARef;
joeata2wh 0:fa185766e039 24 float perc = tval * 100.0;
joeata2wh 0:fa185766e039 25 unsigned short tvalu16 = ain.read_u16 ();
joeata2wh 0:fa185766e039 26
joeata2wh 0:fa185766e039 27 printf("adc %s R=%3.3f V=%3.3f%% U16=%u\r\n",label, tval, volts, tvalu16);
joeata2wh 0:fa185766e039 28
joeata2wh 0:fa185766e039 29 return tval;
joeata2wh 0:fa185766e039 30 }
joeata2wh 0:fa185766e039 31
joeata2wh 0:fa185766e039 32
joeata2wh 0:fa185766e039 33 int main() {
joeata2wh 0:fa185766e039 34
joeata2wh 0:fa185766e039 35 while(1) {
joeata2wh 0:fa185766e039 36 myled = !myled; // toggle led
joeata2wh 0:fa185766e039 37 readPrint(aA7, "PA_7");
joeata2wh 0:fa185766e039 38 readPrint(aA6, "PA_6");
joeata2wh 0:fa185766e039 39 readPrint(aA5, "PA_5");
joeata2wh 0:fa185766e039 40 readPrint(aA4, "PA_4");
joeata2wh 0:fa185766e039 41 readPrint(aA3, "PA_3");
joeata2wh 0:fa185766e039 42 readPrint(aA2, "PA_2");
joeata2wh 0:fa185766e039 43 readPrint(aA1, "PA_1");
joeata2wh 0:fa185766e039 44 readPrint(aA0, "PA_0");
joeata2wh 0:fa185766e039 45
joeata2wh 0:fa185766e039 46 readPrint(aB0, "PB_0");
joeata2wh 0:fa185766e039 47 readPrint(aB1, "PB_1");
joeata2wh 0:fa185766e039 48 printf("\r\n\r\n");
joeata2wh 0:fa185766e039 49 wait(7.0);
joeata2wh 0:fa185766e039 50
joeata2wh 0:fa185766e039 51 }
joeata2wh 0:fa185766e039 52 }