mcp3008.h

00001 /**
00002  * @file mcp32008.h
00003  */
00004 
00005 #include "mbed.h"
00006 
00007 
00008 #ifndef MCP3008_H
00009 #define MCP3008_H
00010 
00011 
00012 /** Polarity setting for differential inputs.
00013  *
00014  * POL_EVEN_POSITIVE sets channel [0|2|4|6] as the positive side and channel
00015  * [1|3|5|7] as the negative side. POL_EVEN_NEGATIVE sets the opposite.
00016  */
00017 enum Polarity {
00018     POL_EVEN_POSITIVE,
00019     POL_EVEN_NEGATIVE
00020 };
00021 
00022 
00023 /** Class for interfacing to the MCP3008 SPI-based ADC.
00024  *
00025  */
00026 class MCP3008
00027 {
00028 public:
00029     /** Create an MCP3008 object.
00030      *
00031      * @param bus An SPI bus object.
00032      * @param cs The name of a pin to use as the chip select.
00033      */
00034     MCP3008(SPI* p_bus, PinName cs);
00035     ~MCP3008();
00036     
00037     /** Read from a single-ended input.
00038      *
00039      * @param channel The channel number to read from.
00040      *
00041      * @param returns The sampled value as a float between 0.0 and 1.0.
00042      */
00043     float read_input(int channel);
00044     
00045     /** Read from a single-ended input.
00046      *
00047      * @param channel The channel number to read from.
00048      *
00049      * @param returns The sampled value as a unsigned int16_t  between 0 and 1024.
00050      */
00051     uint16_t read_input_u16(int channel);
00052     
00053     /** Read from a pair of differential inputs.
00054      *
00055      * In differential mode, the channels are referred to as 0 to 3, with
00056      * polarity set in a separate parameter. This avoids the user having to set
00057      * the polarity as part of the channel number or having channel numbers
00058      * increase by two (i.e. the channels being 0, 2, 4, and 6).
00059      *
00060      * @param channel The channel number to read from.
00061      * @param polarity The polarity of the differential signal.
00062      *
00063      * @param returns The sampled value as a float between 0.0 and 1.0.
00064      */
00065     //float read_diff_input(int channel, Polarity polarity);
00066   
00067 private:
00068     DigitalOut m_cs;
00069     SPI* m_p_bus;
00070     
00071     void select();
00072     void deselect();
00073 };
00074 
00075 
00076 #endif