Gerhard Neumaier / Mbed 2 deprecated Nucleo_IIC_8574a_ana_ledband

Data send to IIC-board with PCF8574a IC Data comming from analog-value Pin A0 = PA_0 Nucleo-board you see a 8bit light strip as a result

Dependencies:   mbed

Testboard IIC with different ICs like PCF8574a PCF8591 etc:

/media/uploads/schlaumaier54/nucleo_steckboard_iic_birk.jpg

Download Programmbeschreibung:

/media/uploads/schlaumaier54/led_band8bitiic_analog_ein.pdf

Neumaier 2018

main.cpp@0:89b72ed83c96, 2015-08-20 (annotated)

Committer:
schlaumaier54
Date:
Thu Aug 20 21:48:46 2015 +0000
Revision:
0:89b72ed83c96
Data send to IIC-board with PCF8574a IC; Data comming from analog-value Pin A0 = PA_0 Nucleo-board; you see a 8bit light strip as a result

Who changed what in which revision?

UserRevisionLine numberNew contents of line
schlaumaier54 0:89b72ed83c96 1 /*Data send to IIC-board with PCF8574a IC
schlaumaier54 0:89b72ed83c96 2 Data comming from analog-value Pin A0 = PA_0 Nucleo-board
schlaumaier54 0:89b72ed83c96 3 you see a 8bit light strip as a result
schlaumaier54 0:89b72ed83c96 4 Aug. 2015 G. Neumaier Gewerblich-Technische Schule Offenburg Germany
schlaumaier54 0:89b72ed83c96 5 */
schlaumaier54 0:89b72ed83c96 6
schlaumaier54 0:89b72ed83c96 7 #include "mbed.h"
schlaumaier54 0:89b72ed83c96 8 #define PCF8574a_ADDR 0x72 // PCF8574a address IIC-board Birk
schlaumaier54 0:89b72ed83c96 9
schlaumaier54 0:89b72ed83c96 10 I2C i2c(I2C_SDA, I2C_SCL); //IIC Pins SDA and SCL for ARDUINO pinheader Nucleo-board
schlaumaier54 0:89b72ed83c96 11 //SCL and SPA pullup resistors 2k2Ohm to+5Volt
schlaumaier54 0:89b72ed83c96 12 DigitalOut myled(LED1); //LED on Nucleo-board
schlaumaier54 0:89b72ed83c96 13 AnalogIn analog_value0(A0); //same as Pin PA_0
schlaumaier54 0:89b72ed83c96 14 Serial pc(SERIAL_TX, SERIAL_RX);
schlaumaier54 0:89b72ed83c96 15
schlaumaier54 0:89b72ed83c96 16 int main()
schlaumaier54 0:89b72ed83c96 17 {
schlaumaier54 0:89b72ed83c96 18 float mess0;
schlaumaier54 0:89b72ed83c96 19 unsigned char mess1, x, LEDs8;
schlaumaier54 0:89b72ed83c96 20 char data_write[2]; //must be char!!
schlaumaier54 0:89b72ed83c96 21 // char data_read[2]; //read buffer
schlaumaier54 0:89b72ed83c96 22
schlaumaier54 0:89b72ed83c96 23 unsigned char speicher[9] = {0xff, 0x7f, 0x3f, 0x1f, 0x0f, 0x07, 0x03, 0x01,0x00}; //data for light strip
schlaumaier54 0:89b72ed83c96 24 data_write[0] = 0xf2; //LEDs low aktiv dummy
schlaumaier54 0:89b72ed83c96 25 int status = i2c.write(PCF8574a_ADDR , data_write, 1, 0);
schlaumaier54 0:89b72ed83c96 26 if (status != 0) // Error no acknowledge detected
schlaumaier54 0:89b72ed83c96 27 {
schlaumaier54 0:89b72ed83c96 28 while (1) //-> endless loop when error no IIC-IC detected
schlaumaier54 0:89b72ed83c96 29 {
schlaumaier54 0:89b72ed83c96 30 myled = !myled;
schlaumaier54 0:89b72ed83c96 31 wait(0.7);
schlaumaier54 0:89b72ed83c96 32 }
schlaumaier54 0:89b72ed83c96 33 }
schlaumaier54 0:89b72ed83c96 34
schlaumaier54 0:89b72ed83c96 35 while (1) //endless loop
schlaumaier54 0:89b72ed83c96 36 {
schlaumaier54 0:89b72ed83c96 37 mess0 = analog_value0.read(); // Converts and read the analog input value (value from 0.0 to 1.0)
schlaumaier54 0:89b72ed83c96 38 mess0 = mess0 * 255; // Change the value to be in the 0 to 255 range -> 8bit
schlaumaier54 0:89b72ed83c96 39 mess1 = (char) mess0; //type converting from float to char(8bit)
schlaumaier54 0:89b72ed83c96 40 printf("Analogvalue0 = %.1f \r\n", mess0); //Rs232 output-> You will see this in terminalprogram on PC
schlaumaier54 0:89b72ed83c96 41 //%.1f -> display 1 digit after comma
schlaumaier54 0:89b72ed83c96 42 //
schlaumaier54 0:89b72ed83c96 43 x= mess1/29; //Remainder of the division falls away, only whole numbers
schlaumaier54 0:89b72ed83c96 44 LEDs8= speicher[x]; //brings accordingly x values aus dem array "speicher"
schlaumaier54 0:89b72ed83c96 45 data_write[0] = ~LEDs8; //8bit analog-value ~ inverted leds lowaktiv!!
schlaumaier54 0:89b72ed83c96 46 i2c.write(PCF8574a_ADDR , data_write, 1, 1); // no stop
schlaumaier54 0:89b72ed83c96 47 //you see a digital 8bit counter at leds contacted to IC PCF8574
schlaumaier54 0:89b72ed83c96 48 }
schlaumaier54 0:89b72ed83c96 49
schlaumaier54 0:89b72ed83c96 50 }
schlaumaier54 0:89b72ed83c96 51