Spi.h

Go to the documentation of this file.

 
#ifndef _SPI_H
#define _SPI_H
 
#include <stdint.h>
#include "ReadWriteBits.h"
 
// ---Hardware i/o types---
typedef uint8_t volatile * const spi_reg; // i/o reg address
typedef uint8_t const spi_bit; // bit index into i/o reg
 
// ---i/o Registers---
extern spi_reg Spi_PortDirection;
extern spi_reg Spi_PortInput;
extern spi_reg Spi_PortOutput;
extern spi_reg Spi_PortPullup;
extern spi_reg Spi_SPCR;
extern spi_reg Spi_SPSR;
extern spi_reg Spi_SPDR;
 
// ---i/o Pins---
extern spi_bit Spi_DataReady;
extern spi_bit Spi_Ss;
extern spi_bit Spi_Mosi;
extern spi_bit Spi_Miso;
extern spi_bit Spi_Sck;
 
// ---i/o Bits---
extern spi_bit Spi_MasterSlaveSelect; // bit MSTR in SPCR (0x2C)
extern spi_bit Spi_ClockBit0;         // bit 0 in SPCR (0x2C)
extern spi_bit Spi_ClockBit1;         // bit 1 in SPCR (0x2C)
extern spi_bit Spi_DoubleClock;       // bit 0 in SPSR (0x2D)
extern spi_bit Spi_Enable;            // bit 6 in SPCR (0x2C)
extern spi_bit Spi_InterruptEnable;   // bit 7 in SPCR (0x2C)
extern spi_bit Spi_InterruptFlag;     // bit 7 in SPSR (0x2D)
 
#ifdef USE_FAKES
#include "Spi_faked.h" // declare fakes
#endif
 
// ---Private---
inline void _EnableSpiModule(void)
{
    SetBit(Spi_SPCR, Spi_Enable);
    // ---Expected Assembly---
    // in r24, 0x2c;
    // ori r24, 0x40;
    // out 0x2c, r24
    // This is three instructions because SPCR is outside the
    // address range for using `sbi`.
}
inline bool _SpiTransferIsDone(void)
{
    return BitIsSet(Spi_SPSR, Spi_InterruptFlag);
}
 
// ---API (Go to the Doxygen documentation of this file)---
inline uint8_t ReadSpiStatusRegister(void)
{
    return *Spi_SPSR;
    // ---Expected Assembly---
    // in   r24, 0x2d   ; 45
}
inline uint8_t ReadSpiDataRegister(void)
{
    return *Spi_SPDR;
    // ---Expected Assembly---
    // in   r24, 0x2e   ; 46
}
inline void ClearSpiInterruptFlag(void)
{
 
    ReadSpiStatusRegister(); // in  r24, 0x2d
    ReadSpiDataRegister(); // in    r24, 0x2e
}
 
// ---API functions that call fakes when testing---
//
 
#endif // _SPI_H