Revision 0:3dc2ed1d2069, committed 2015-08-20

Comitter:

schlaumaier54

Date:

Thu Aug 20 20:41:10 2015 +0000

Commit message:

AnalogvalueA0 over i2c-Bus to IC PCF8574a. You see there a digital 8bit counter depending of the analogvalue.

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Aug 20 20:41:10 2015 +0000
@@ -0,0 +1,48 @@
+/*
+Data send to IIC-board with PCF8574a IC
+Data comming from analog-value Pin A0 = PA_0 Nucleo-board
+you see a digital 8bit counter as a result
+Aug. 2015 G. Neumaier Gewerblich-Technische Schule Offenburg Germany
+*/
+
+#include "mbed.h"
+#define PCF8574a_ADDR  0x72 // PCF8574a address IIC-board Birk 
+
+I2C i2c(I2C_SDA, I2C_SCL); //IIC Pins SDA and SCL for ARDUINO pinheader Nucleo-board
+            //SCL and SPA pullup resistors 2k2Ohm to+5Volt
+DigitalOut myled(LED1); //LED on Nucleo-board
+AnalogIn analog_value0(A0);      //same as Pin PA_0 
+Serial pc(SERIAL_TX, SERIAL_RX);
+ 
+int main()
+{
+    float mess0;
+    unsigned char mess1;
+    char data_write[2]; //must be char!!
+ //   char data_read[2]; //read buffer
+    data_write[0] = 0xf2; //LEDs low aktiv  dummy
+    int status = i2c.write(PCF8574a_ADDR , data_write, 1, 0);
+    if (status != 0) // Error  no acknowledge detected 
+    { 
+        while (1) //-> endless loop when error no IIC-IC detected
+        {   
+        myled = !myled;
+        wait(0.7);
+        }
+    }
+ 
+    while (1) //endless loop
+        {
+        mess0 = analog_value0.read(); // Converts and read the analog input value (value from 0.0 to 1.0)
+        mess0 = mess0 * 255; // Change the value to be in the 0 to 255 range -> 8bit
+        mess1 = (char) mess0;  //type converting from float to char(8bit)
+        printf("Analogvalue0 = %.1f \r\n", mess0);  //Rs232 output-> You will see this in terminalprogram on PC
+        //%.1f -> display 1 digit after comma
+        // 
+        data_write[0] = ~mess1; //8bit analog-value  ~ inverted  leds lowaktiv!!
+        i2c.write(PCF8574a_ADDR , data_write, 1, 1); // no stop 
+        //you see a digital 8bit counter at leds contacted to IC PCF8574
+    }
+ 
+}
+ 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Thu Aug 20 20:41:10 2015 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/ed8466a608b4
\ No newline at end of file