DS1302.hh

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#ifndef COSA_DS1302_HH
#define COSA_DS1302_HH

#include "Cosa/OutputPin.hh"
#include "Cosa/IOPin.hh"
#include "Cosa/Time.hh"

class DS1302 {
public:
  static const uint8_t RTC_START = 0;

  static const size_t RAM_MAX = 31;

  static const uint8_t RAM_START = 32;

  static const uint8_t RAM_END = RAM_START + RAM_MAX;

  DS1302(Board::DigitalPin cs = Board::D4,
         Board::DigitalPin sda = Board::D3,
         Board::DigitalPin clk = Board::D2) :
    m_cs(cs, 0),
    m_sda(sda, IOPin::OUTPUT_MODE),
    m_clk(clk, 0)
  {}

  /*
   * Low level RTC access function. Read data from the clock register
   * or static memory on device.
   * @param[in] addr device address.
   * @return data.
   */
  uint8_t read(uint8_t addr);

  /*
   * Low level RTC access function. Write given data to the clock
   * register or static memory on device.
   * @param[in] addr device address.
   * @param[in] data to write.
   */
  void write(uint8_t addr, uint8_t data);

  void write_protect(bool flag)
    __attribute__((always_inline))
  {
    write(WP, flag ? 0x80 : 0x00);
  }

  void get_time(time_t& now);

  void set_time(time_t& now);

  uint8_t read_ram(uint8_t addr)
    __attribute__((always_inline))
  {
    return (read(RAM_START | (addr & ADDR_MASK)));
  }

  void write_ram(uint8_t addr, uint8_t data)
    __attribute__((always_inline))
  {
    write(RAM_START | (addr & ADDR_MASK), data);
  }

  void read_ram(void* buf, size_t size);

  void write_ram(void* buf, size_t size);

protected:
  static const uint8_t WP = 0x07;

  enum {
    WRITE = 0x80,               
    READ = 0x81,                
    RTC_BURST = 0xbe,           
    RAM_BURST = 0xfe,           
    ADDR_MASK = 0x3f            
  } __attribute__((packed));

  OutputPin m_cs;               
  IOPin m_sda;                  
  OutputPin m_clk;              

  uint8_t read();

  void write(uint8_t data);
};

#endif