DS2408.h

00001 /**
00002  * Library for DS2408 on top of OneWire library
00003 */
00004 
00005 #ifndef XDOT_DS2408_H
00006 #define XDOT_DS2408_H
00007 
00008 #include "../config.h"
00009 #include "OneWire.h"
00010 
00011 const uint8_t DS2408_NRETRIES = 5;
00012 
00013 /**
00014  *  @class DS2408
00015  *  @brief This class abstracts communicating with the DS2408 port expander.
00016  *  The OneWire library is used for physical layer communication and this class
00017  *  simply makes it easy to communicate with this one chip.
00018  */
00019 class DS2408
00020 {
00021 public:
00022     enum DS2408RegAddr {
00023         pioLogicStateReg         = 0x88,
00024         pioOutputLatchStateReg   = 0x89,
00025         pioActivityStateReg      = 0x8A,
00026         condSearchChSelMaskReg   = 0x8B,
00027         condSearchChPolMaskReg   = 0x8C,
00028         ctrlStatusReg            = 0x8D
00029     };
00030 
00031     /**
00032     * @brief DS2408 constructor
00033     *
00034     * @details Just initialized internal variables and disables test mode
00035     *
00036     * On Entry:
00037     *     @param[in] owMaster - reference to 1-wire master
00038     *     @param[in] romAddr - 64-bit address of ROM
00039     *
00040     * On Exit:
00041     *
00042     * @return
00043     */
00044     DS2408(OneWire *owMaster, uint8_t romAddr[8]);
00045 
00046     /**
00047     * @brief registerRead()
00048     *
00049     * @details reads state of pio
00050     *
00051     *
00052     * On Exit:
00053     *     @param[in]  addr - per datasheet valid registers are from 0x88 to 0x8D.
00054     *     Note value will be automatically promoted to 16-bit value.
00055     *     @param[out] val - register value
00056     *
00057     * @return Result of operation zero for success
00058     */
00059     CmdResult registerRead(uint8_t addr, uint8_t &val);
00060 
00061     CmdResult registerReadReliable(uint8_t addr, uint8_t &val);
00062 
00063     /**
00064     * @brief pioLogicRead()
00065     *
00066     * @details Uses regisrterRead to get logic values
00067     *
00068     *
00069     * On Exit:
00070     *     @param[out] val - lsb represents the state of the pio
00071     *
00072     * @return Result of operation zero for success
00073     */
00074     CmdResult pioLogicRead(uint8_t &val);
00075 
00076     /**
00077     * @brief pioLogicReliableRead()
00078     *
00079     * @details Uses regisrterRead to get logic values.  Then reads again to check for bit errors.
00080     *
00081     *
00082     * On Exit:
00083     *     @param[out] val - lsb represents the state of the pio
00084     *
00085     * @return Result of operation zero for success
00086     */
00087     CmdResult pioLogicReliableRead(uint8_t &val);
00088     // TODO implement other register based functions
00089 
00090     /**
00091     * @brief pioLogicReliableWrite()
00092     *
00093     * @details writes to pio.  Note 0 means active pull down and 1 high-Z to
00094     * allow PIO to float high.  This will automatically retry for DS2408_NRETRIES
00095     * times.
00096     *
00097     * On Entry:
00098     *    @param[in] val - Value for IO.
00099     *
00100     * @return CmdResult - result of operation
00101     */
00102     CmdResult pioLogicReliableWrite(uint8_t val);
00103 
00104     /**
00105     * @brief pioLogicWrite()
00106     *
00107     * @details writes to pio.  Note 0 means active pull down and 1 high-Z to
00108     * allow PIO to float high.
00109     *
00110     * On Entry:
00111     *    @param[in] val - Value for IO.
00112     *
00113     * @return CmdResult - result of operation
00114     */
00115     CmdResult pioLogicWrite(uint8_t val);
00116 
00117 private:
00118     OneWire *mMaster;
00119     uint8_t mRomAddr[8];
00120 
00121     /**
00122     * @brief disableTestMode()
00123     *
00124     * @details Per datasheet if slew power on has a specific slew rate the
00125     * chip may enter a test mode.  See page 38 of application information.
00126     *
00127     * @return CmdResult - result of operation
00128     */
00129     CmdResult disableTestMode();
00130 
00131 };
00132 
00133 #endif