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@2:dc3e84d595c3, 2016-03-21 (annotated)

Committer:
joeata2wh
Date:
Mon Mar 21 03:42:56 2016 +0000
Revision:
2:dc3e84d595c3
Parent:
1:90d213185462
Child:
3:47148198f5f2
got it working with the adafruit library

Who changed what in which revision?

UserRevisionLine numberNew contents of line
joeata2wh 1:90d213185462 1 /* Example of Reading all the ADC pins PIN and display ot OLED display using
joeata2wh 2:dc3e84d595c3 2 Nucleo_F303K8 by Joseph Ellsworth CTO A2WH - Free for all but no warranty, no promises
joeata2wh 2:dc3e84d595c3 3 Displays voltage read from first 2 ADC lines on OLED display
joeata2wh 2:dc3e84d595c3 4
joeata2wh 2:dc3e84d595c3 5 Used to Drive:
joeata2wh 1:90d213185462 6 ebay part http://www.ebay.com/itm/152000005331?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
joeata2wh 1:90d213185462 7 0-96-I2C-IIC-SPI-Serial-White-OLED-LCD-LED-Display-Module-128X64
joeata2wh 1:90d213185462 8 The Datasheet. https://www.adafruit.com/datasheets/SSD1306.pdf
joeata2wh 2:dc3e84d595c3 9
joeata2wh 1:90d213185462 10 Unfortunately this part never turns on using the SSD1308 library.
joeata2wh 2:dc3e84d595c3 11 but did find that the https://developer.mbed.org/users/nkhorman/code/Adafruit_GFX/
joeata2wh 2:dc3e84d595c3 12 library works. Unfortunately the Adafruit library doesn't include the scroll functionality.
joeata2wh 2:dc3e84d595c3 13
joeata2wh 1:90d213185462 14 Using my I2C address scanner I found that it responds on Added 120 (x78) ,121 (x79)
joeata2wh 2:dc3e84d595c3 15 and when the part was unsoldered nothing responded on 120 or 121. According to
joeata2wh 1:90d213185462 16 to the page #19 (8.1.5) of the data sheet the I2C address should be 011110
joeata2wh 2:dc3e84d595c3 17 which seems to map correctly to dec=120 hex=79
joeata2wh 2:dc3e84d595c3 18
joeata2wh 1:90d213185462 19 */
joeata2wh 0:fa185766e039 20
joeata2wh 0:fa185766e039 21 #include "mbed.h"
joeata2wh 2:dc3e84d595c3 22 //#include "SSD1308.h"
joeata2wh 2:dc3e84d595c3 23 #include "Adafruit_SSD1306.h"
joeata2wh 0:fa185766e039 24
joeata2wh 1:90d213185462 25 //#include "mbed_logo.h"
joeata2wh 2:dc3e84d595c3 26
joeata2wh 2:dc3e84d595c3 27 //Pin Defines for I2C Bus
joeata2wh 2:dc3e84d595c3 28 #define D_SDA PB_7 // specific for Nucleo-F303K8
joeata2wh 2:dc3e84d595c3 29 #define D_SCL PB_6 // specific for Nucleo-F303K8
joeata2wh 2:dc3e84d595c3 30 I2C i2c(D_SDA, D_SCL);
joeata2wh 2:dc3e84d595c3 31
joeata2wh 2:dc3e84d595c3 32 // Host PC Communication channels
joeata2wh 2:dc3e84d595c3 33 Serial pc(USBTX, USBRX); // tx, rx
joeata2wh 2:dc3e84d595c3 34
joeata2wh 2:dc3e84d595c3 35 AnalogIn pa0(PA_0);
joeata2wh 2:dc3e84d595c3 36 AnalogIn pa1(PA_1);
joeata2wh 2:dc3e84d595c3 37
joeata2wh 0:fa185766e039 38 DigitalOut myled(LED1);
joeata2wh 0:fa185766e039 39 const float voltMeterARef = 3.3;
joeata2wh 0:fa185766e039 40
joeata2wh 2:dc3e84d595c3 41 // an I2C sub-class that provides a constructed default
joeata2wh 2:dc3e84d595c3 42 class I2CPreInit : public I2C
joeata2wh 2:dc3e84d595c3 43 {
joeata2wh 2:dc3e84d595c3 44 public:
joeata2wh 2:dc3e84d595c3 45 I2CPreInit(PinName sda, PinName scl) : I2C(sda, scl) {
joeata2wh 2:dc3e84d595c3 46 frequency(400000);
joeata2wh 2:dc3e84d595c3 47 start();
joeata2wh 2:dc3e84d595c3 48 };
joeata2wh 2:dc3e84d595c3 49 };
joeata2wh 0:fa185766e039 50
joeata2wh 2:dc3e84d595c3 51
joeata2wh 2:dc3e84d595c3 52 I2CPreInit gI2C(D_SDA,D_SCL);
joeata2wh 2:dc3e84d595c3 53 Adafruit_SSD1306_I2c gOled2(gI2C,PB_5);
joeata2wh 1:90d213185462 54
joeata2wh 0:fa185766e039 55
joeata2wh 2:dc3e84d595c3 56 float readPrint(AnalogIn ain, char *label)
joeata2wh 2:dc3e84d595c3 57 {
joeata2wh 2:dc3e84d595c3 58 float tval = ain.read();
joeata2wh 2:dc3e84d595c3 59 float volts = tval * voltMeterARef;
joeata2wh 2:dc3e84d595c3 60 float perc = tval * 100.0;
joeata2wh 2:dc3e84d595c3 61 unsigned short tvalu16 = ain.read_u16 ();
joeata2wh 2:dc3e84d595c3 62 printf("adc %s R=%3.3f V=%3.3f%% U16=%u\r\n",label, tval, volts, tvalu16);
joeata2wh 2:dc3e84d595c3 63 gOled2.printf("%s=%3.3fV\r\n",label,volts);
joeata2wh 2:dc3e84d595c3 64 gOled2.display();
joeata2wh 2:dc3e84d595c3 65 return tval;
joeata2wh 2:dc3e84d595c3 66 }
joeata2wh 2:dc3e84d595c3 67
joeata2wh 2:dc3e84d595c3 68
joeata2wh 2:dc3e84d595c3 69 int main()
joeata2wh 2:dc3e84d595c3 70 {
joeata2wh 2:dc3e84d595c3 71 // Display with the Adafruit Library
joeata2wh 2:dc3e84d595c3 72 gOled2.printf("%ux%u OLED Display\r\n", gOled2.width(), gOled2.height());
joeata2wh 2:dc3e84d595c3 73 wait(5);
joeata2wh 2:dc3e84d595c3 74 gOled2.clearDisplay();
joeata2wh 0:fa185766e039 75 while(1) {
joeata2wh 2:dc3e84d595c3 76 myled = !myled;
joeata2wh 2:dc3e84d595c3 77 gOled2.clearDisplay();
joeata2wh 2:dc3e84d595c3 78 gOled2.setTextCursor(1,1);
joeata2wh 2:dc3e84d595c3 79 readPrint(pa0, "PA_0");
joeata2wh 2:dc3e84d595c3 80 wait(0.1);
joeata2wh 2:dc3e84d595c3 81 gOled2.setTextCursor(1,10);
joeata2wh 2:dc3e84d595c3 82 readPrint(pa1, "PA_1");
joeata2wh 2:dc3e84d595c3 83 wait(3.0);
joeata2wh 0:fa185766e039 84 }
joeata2wh 2:dc3e84d595c3 85
joeata2wh 2:dc3e84d595c3 86
joeata2wh 0:fa185766e039 87 }