Jimmy Hack / MAX500

The MAX500 is an 8 bit DAC that can output to higher voltages (~12V). The chip has 4 onboard DAC channels.

Dependencies:   DAC

DAC_SPI/DAC_SPI.h@0:b74d88185698, 2012-07-03 (annotated)

Committer:
JimmyTheHack
Date:
Tue Jul 03 03:22:59 2012 +0000
Revision:
0:b74d88185698
updated DAC_SPI library to have virtual select function

Who changed what in which revision?

UserRevisionLine numberNew contents of line
JimmyTheHack 0:b74d88185698 1 #ifndef DAC_SPI_H
JimmyTheHack 0:b74d88185698 2 #define DAC_SPI_H
JimmyTheHack 0:b74d88185698 3 #include "mbed.h"
JimmyTheHack 0:b74d88185698 4
JimmyTheHack 0:b74d88185698 5 /* a basic parent library for use with DACs controlled via SPI. Individual hardware implementations will need their own libraries.
JimmyTheHack 0:b74d88185698 6 This provides basic initialization of common pins and provides a serial channel. Doesn't provide a lot of added functionality, but serves as an interface for the SPI library.
JimmyTheHack 0:b74d88185698 7 */
JimmyTheHack 0:b74d88185698 8 class DAC_SPI
JimmyTheHack 0:b74d88185698 9 {
JimmyTheHack 0:b74d88185698 10 public:
JimmyTheHack 0:b74d88185698 11 DAC_SPI(int SPIchannelNum, PinName CS, PinName LDAC);
JimmyTheHack 0:b74d88185698 12 virtual void select(char DACvalue); //choose the active DAC
JimmyTheHack 0:b74d88185698 13 virtual void write(int DACvalue) =0; //write a value to the Digital Analog Converter
JimmyTheHack 0:b74d88185698 14 virtual void write_mV(int millivolts) =0; //write a value to the Digital Analog Converter specified in mV (may require appropriate scaling factor)
JimmyTheHack 0:b74d88185698 15
JimmyTheHack 0:b74d88185698 16 /** Manually change the SPI frequency
JimmyTheHack 0:b74d88185698 17 * @param freq Desired frequency in hertz: must be a value supported by both the mbed and DAC. The MCP4922 supports frequencies to 20MHz.
JimmyTheHack 0:b74d88185698 18 */
JimmyTheHack 0:b74d88185698 19 void frequency(int freq);
JimmyTheHack 0:b74d88185698 20 //set the number of bits for DAC
JimmyTheHack 0:b74d88185698 21 void messageBits(int bits);
JimmyTheHack 0:b74d88185698 22 //DigitalOut SCK;
JimmyTheHack 0:b74d88185698 23 /** The currently selected DAC channel. 0 for DAC A, 1 for DAC B, etc*/
JimmyTheHack 0:b74d88185698 24 char DACselect;
JimmyTheHack 0:b74d88185698 25 DigitalOut CS; //serial chip select pin
JimmyTheHack 0:b74d88185698 26 DigitalOut LDAC; //synchronize pin to update both DACs together
JimmyTheHack 0:b74d88185698 27 SPI * DACspi; //SPI channel. 0 for p5-p7, 1 for p11-p13
JimmyTheHack 0:b74d88185698 28 };
JimmyTheHack 0:b74d88185698 29
JimmyTheHack 0:b74d88185698 30 extern SPI SPI_A; //channel A SPI (pins 5,7)
JimmyTheHack 0:b74d88185698 31 extern SPI SPI_B; //channel B SPI (pins 11,13)
JimmyTheHack 0:b74d88185698 32
JimmyTheHack 0:b74d88185698 33 #endif //DAC_H