SpiSlave.h File Reference

#include <stdint.h>
#include <stdbool.h>
#include "ReadWriteBits.h"
#include "Spi.h"

Go to the source code of this file.

Functions
void	_SignalDataReady (void)
void	_SignalDataNotReady (void)
void	DisableSpiInterrupt (void)
void	EnableSpiInterrupt (void)
void	SpiSlaveInit (void)
void	SpiSlaveTxByte (uint8_t input_byte)
void	SpiSlaveTx (uint8_t const *input_buffer, uint16_t nbytes)

Detailed Description

API

void DisableSpiInterrupt(void);
void EnableSpiInterrupt(void);
void SpiSlaveInit(void);
void SpiSlaveTxByte(uint8_t input_byte);
void SpiSlaveTx(uint8_t const *input_buffer, uint16_t nbytes);

Definition in file SpiSlave.h.

Function Documentation

_SignalDataNotReady()

void _SignalDataNotReady ( void  )

inline

Drive Data Ready HIGH.

Definition at line 31 of file SpiSlave.h.

_SignalDataReady()

void _SignalDataReady ( void  )

inline

_SignalDataReady behavior:

• drives DataReady LOW
  

SPI Slave outputs signal Data Ready.

• Data Ready LOW signals next byte of data is ready.
  
• SPI Master waits for Data Ready LOW before reading a byte from the SPI Slave.
  
• SPI Slave drives Data Ready HIGH after each byte of SPI transfer.

Definition at line 14 of file SpiSlave.h.

DisableSpiInterrupt()

void DisableSpiInterrupt ( void  )

inline

Clear SPIE bit in SPCR to disable the SPI ISR.

DisableSpiInterrupt behavior:

• clears the SPI Interrupt Enable bit
  

Note:

• Even with the SPI ISR disabled, interrupt flag bit SPIF in register SPSR is still set when a serial transfer completes.
  
• Check the flag by calling _SpiTransferIsDone()
  
• Clear SPIF manually by calling ClearSpiInterruptFlag()
  

Definition at line 48 of file SpiSlave.h.

EnableSpiInterrupt()

void EnableSpiInterrupt ( void  )

inline

EnableSpiInterrupt behavior:

• clears SPI interrupt flag
  
• enables SPI transfer complete interrupt
  
• consumes 6 cycles
  

Set SPIE bit in SPCR to execute the SPI ISR when:

• the Global Interrupt Enable bit is set in SREG
  
• bit SPIF in register SPSR is set
  
  • bit SPIF in register SPSR is set when a serial transfer completes
    
  • SPIF is cleared when executing the SPI ISR
    
  • alternatively, SPIF is cleared by first reading the SPI status register, then accessing the SPI data register
    

Definition at line 77 of file SpiSlave.h.

SpiSlaveInit()

void SpiSlaveInit ( void  )

inline

SpiSlaveInit behavior:

• makes DataReady an output pin
  
• idles DataReady high
  
• makes Miso an output pin
  
• enables SPI
  
• enables SPI interrupt
  

Definition at line 118 of file SpiSlave.h.

SpiSlaveTx()

void SpiSlaveTx ( uint8_t const *  input_buffer, uint16_t  nbytes  )

inline

SpiSlaveTx behavior:

• sends nbytes of input buffer to SpiMaster
  

Definition at line 202 of file SpiSlave.h.

SpiSlaveTxByte()

void SpiSlaveTxByte ( uint8_t  input_byte )

inline

Transmit a byte and ignore byte received.

SpiSlaveTxByte behavior:

• loads SPI data register with input byte
  
• disables SPI ISR before signaling data ready
  
• drives DataReady LOW to signal data is ready
  
• waits until SPI transfer is done
  
• drives DataReady HIGH immediately after SPI transfer finishes
  
• enables SPI ISR after transfer
  

Definition at line 150 of file SpiSlave.h.