src/modules/utils/currentcontrol/mcp4451.h

   1 #ifndef MCP4451_H
   2 #define MCP4451_H
   3
   4 #include "libs/Kernel.h"
   5 #include "I2C.h" // mbed.h lib
   6 #include "libs/utils.h"
   7 #include "DigipotBase.h"
   8 #include <string>
   9 #include <math.h>
  10
  11 class MCP4451 : public DigipotBase {
  12     public:
  13         MCP4451(){
  14             // I2C com
  15             this->i2c = new mbed::I2C(p9, p10);
  16             this->i2c->frequency(20000);
  17             for (int i = 0; i < 8; i++) currents[i] = -1;
  18         }
  19
  20         ~MCP4451(){
  21             delete this->i2c;
  22         }
  23
  24         void set_current( int channel, float current )
  25         {
  26             if(current < 0) {
  27                 currents[channel]= -1;
  28                 return;
  29             }
  30             current = min( (float) max( current, 0.0f ), this->max_current );
  31             currents[channel] = current;
  32             char addr = 0x58;
  33             while(channel > 3){
  34                 addr += 0x02;
  35                 channel -= 4;
  36             }
  37
  38             // Initial setup
  39             this->i2c_send( addr, 0x40, 0xff );
  40             this->i2c_send( addr, 0xA0, 0xff );
  41
  42             // Set actual wiper value
  43             char addresses[4] = { 0x00, 0x10, 0x60, 0x70 };
  44             this->i2c_send( addr, addresses[channel], this->current_to_wiper(current) );
  45         }
  46
  47         float get_current(int channel)
  48         {
  49             return currents[channel];
  50         }
  51
  52     private:
  53
  54         void i2c_send( char first, char second, char third ){
  55             this->i2c->start();
  56             this->i2c->write(first);
  57             this->i2c->write(second);
  58             this->i2c->write(third);
  59             this->i2c->stop();
  60         }
  61
  62         char current_to_wiper( float current ){
  63             return char(ceilf(float((this->factor*current))));
  64         }
  65
  66         mbed::I2C* i2c;
  67         float currents[8];
  68 };
  69
  70
  71 #endif