Diff: DAC_SPI.h

Revision:

1:679fa19d91b2

diff -r bce9b1450b19 -r 679fa19d91b2 DAC_SPI.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DAC_SPI.h	Tue Jul 16 05:52:01 2013 +0000
@@ -0,0 +1,33 @@
+#ifndef DAC_SPI_H
+#define DAC_SPI_H
+#include "mbed.h"
+
+/* a basic parent library for use with DACs controlled via SPI.  Individual hardware implementations will need their own libraries.
+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.
+*/
+class DAC_SPI
+{
+    public:
+    DAC_SPI(int SPIchannelNum, PinName CS,  PinName LDAC);
+    virtual void select(char DACvalue); //choose the active DAC
+    virtual void write(int DACvalue) =0; //write a value to the Digital Analog Converter    
+    virtual void write_mV(int millivolts) =0; //write a value to the Digital Analog Converter specified in mV (may require appropriate scaling factor)
+    
+    /** Manually change the SPI frequency 
+    * @param freq Desired frequency in hertz: must be a value supported by both the mbed and DAC.  The MCP4922 supports frequencies to 20MHz.
+    */
+    void frequency(int freq);
+    //set the number of bits for DAC
+    void messageBits(int bits);
+    //DigitalOut SCK;
+    /** The currently selected DAC channel.  0 for DAC A, 1 for DAC B, etc*/
+    char DACselect;
+    DigitalOut CS;  //serial chip select pin
+    DigitalOut LDAC; //synchronize pin to update both DACs together    
+    SPI * DACspi;  //SPI channel.  0 for p5-p7, 1 for p11-p13
+};
+
+extern SPI SPI_A;  //channel A SPI (pins 5,7)
+extern SPI SPI_B;  //channel B SPI (pins 11,13)
+
+#endif //DAC_H
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