Donal Morrissey / MCP4725

Library for controlling an MCP4725 "12-Bit Digital-to-Analog Converter with EEPROM Memory". There is an accompanying test suite program "MCP_4725_Library_Test" that can be used to test this library.

Dependents:   IGGE_Power MCP4725_Library_Test MCP4725 SinWave ... more

mcp4725.cpp@0:3214e3bbf25c, 2013-10-27 (annotated)

Committer:
donalm
Date:
Sun Oct 27 13:49:35 2013 +0000
Revision:
0:3214e3bbf25c
Child:
5:3e6ffce1eea2
Initial version.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
donalm 0:3214e3bbf25c 1 #include "mcp4725.h"
donalm 0:3214e3bbf25c 2 #include "mbed.h"
donalm 0:3214e3bbf25c 3
donalm 0:3214e3bbf25c 4 MCP4725::MCP4725(PinName sda, PinName scl, BusFrequency bus_frequency, int device_address_bits)
donalm 0:3214e3bbf25c 5 {
donalm 0:3214e3bbf25c 6 _i2c_interface = new I2C(sda, scl);
donalm 0:3214e3bbf25c 7
donalm 0:3214e3bbf25c 8 //Set the frequency
donalm 0:3214e3bbf25c 9 int freq=0;
donalm 0:3214e3bbf25c 10 switch(bus_frequency)
donalm 0:3214e3bbf25c 11 {
donalm 0:3214e3bbf25c 12 case Standard100kHz:
donalm 0:3214e3bbf25c 13 freq = 100000;
donalm 0:3214e3bbf25c 14 break;
donalm 0:3214e3bbf25c 15 case Fast400kHz:
donalm 0:3214e3bbf25c 16 freq = 400000;
donalm 0:3214e3bbf25c 17 break;
donalm 0:3214e3bbf25c 18 case HighSpeed3_4Mhz:
donalm 0:3214e3bbf25c 19 freq = 3400000;
donalm 0:3214e3bbf25c 20 break;
donalm 0:3214e3bbf25c 21 }
donalm 0:3214e3bbf25c 22 _i2c_interface->frequency(freq);
donalm 0:3214e3bbf25c 23
donalm 0:3214e3bbf25c 24 // Assemble the full I2C device address.
donalm 0:3214e3bbf25c 25 _device_address = 0xC0; // Prime the full device address with the device code.
donalm 0:3214e3bbf25c 26 _device_address |= (device_address_bits<<1);
donalm 0:3214e3bbf25c 27 }
donalm 0:3214e3bbf25c 28
donalm 0:3214e3bbf25c 29 int MCP4725::read(enum PowerMode* mode, enum PowerMode* mode_eeprom, int* dac_value, int* dac_value_eeprom, bool* eeprom_write_in_progress)
donalm 0:3214e3bbf25c 30 {
donalm 0:3214e3bbf25c 31 char data[5];
donalm 0:3214e3bbf25c 32 int result;
donalm 0:3214e3bbf25c 33
donalm 0:3214e3bbf25c 34 // Read the raw data from the device.
donalm 0:3214e3bbf25c 35 result = _i2c_interface->read(_device_address, data, sizeof(data)/sizeof(*data), false);
donalm 0:3214e3bbf25c 36
donalm 0:3214e3bbf25c 37 // Parse the raw data, extracting our fields. Refer to MCP4725 ref manual, section 6.2
donalm 0:3214e3bbf25c 38 if (result == 0)
donalm 0:3214e3bbf25c 39 {
donalm 0:3214e3bbf25c 40 *eeprom_write_in_progress = (data[0] & 0x80)? false:true;
donalm 0:3214e3bbf25c 41
donalm 0:3214e3bbf25c 42 *mode = (enum PowerMode) ((data[0] & 0x06)>>1);
donalm 0:3214e3bbf25c 43
donalm 0:3214e3bbf25c 44 *dac_value = (data[1]<<4) + (data[2]>>4);
donalm 0:3214e3bbf25c 45
donalm 0:3214e3bbf25c 46 *mode_eeprom = (enum PowerMode)((data[3] & 0x60)>>5);
donalm 0:3214e3bbf25c 47
donalm 0:3214e3bbf25c 48 *dac_value_eeprom = ((data[3] & 0x0F) <<8) + data[4];
donalm 0:3214e3bbf25c 49 }
donalm 0:3214e3bbf25c 50
donalm 0:3214e3bbf25c 51 return result;
donalm 0:3214e3bbf25c 52 }
donalm 0:3214e3bbf25c 53
donalm 0:3214e3bbf25c 54
donalm 0:3214e3bbf25c 55
donalm 0:3214e3bbf25c 56 int MCP4725::write(enum PowerMode mode, int dac_value, bool writeToEeprom)
donalm 0:3214e3bbf25c 57 {
donalm 0:3214e3bbf25c 58 char data[3]={0};
donalm 0:3214e3bbf25c 59 int write_command;
donalm 0:3214e3bbf25c 60
donalm 0:3214e3bbf25c 61 //Which write command are we to use?
donalm 0:3214e3bbf25c 62 if (writeToEeprom == true)
donalm 0:3214e3bbf25c 63 {
donalm 0:3214e3bbf25c 64 //Write DAC Register and EEPROM
donalm 0:3214e3bbf25c 65 write_command = 3;
donalm 0:3214e3bbf25c 66 }
donalm 0:3214e3bbf25c 67 else
donalm 0:3214e3bbf25c 68 {
donalm 0:3214e3bbf25c 69 //Write DAC Register
donalm 0:3214e3bbf25c 70 write_command = 2;
donalm 0:3214e3bbf25c 71 }
donalm 0:3214e3bbf25c 72
donalm 0:3214e3bbf25c 73 //Assemble our three bytes of data - Refer to MCP4725 ref manual, section 6.
donalm 0:3214e3bbf25c 74 data[0] = (write_command <<5) | ((int)mode<<1);
donalm 0:3214e3bbf25c 75 data[1] = (dac_value>>4);
donalm 0:3214e3bbf25c 76 data[2] = (dac_value<<4);
donalm 0:3214e3bbf25c 77
donalm 0:3214e3bbf25c 78 // Now write them to the device.
donalm 0:3214e3bbf25c 79 return _i2c_interface->write(_device_address, data, sizeof(data)/sizeof(*data), false);
donalm 0:3214e3bbf25c 80 }