125 lines
1.9 KiB
C++
125 lines
1.9 KiB
C++
|
#include "_Spi.h"
|
||
|
|
|
||
|
|
SpiDevice::SpiDevice() {
|
||
|
|
/*
|
||
|
|
*/
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void SpiDevice::begin() {
|
||
|
|
/*
|
||
|
|
|
||
|
|
Use the default chip select pin as specified by
|
||
|
|
the SS define in the header.
|
||
|
|
|
||
|
|
*/
|
||
|
|
begin(SS);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void SpiDevice::begin(byte selectPin) {
|
||
|
|
/*
|
||
|
|
*/
|
||
|
|
_selectPin = selectPin;
|
||
|
|
_initPins();
|
||
|
|
_initSpi();
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void SpiDevice::_initPins() {
|
||
|
|
/*
|
||
|
|
|
||
|
|
Initialise the pins used for SPI communication.
|
||
|
|
|
||
|
|
*/
|
||
|
|
|
||
|
|
pinMode(MOSI, OUTPUT);
|
||
|
|
pinMode(MISO, INPUT);
|
||
|
|
pinMode(SCK, OUTPUT);
|
||
|
|
pinMode(_selectPin, OUTPUT);
|
||
|
|
|
||
|
|
deselect();
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void SpiDevice::_initSpi() {
|
||
|
|
/*
|
||
|
|
|
||
|
|
Initialise SPI system.
|
||
|
|
|
||
|
|
*/
|
||
|
|
|
||
|
|
// From Table 18-5 in ATmega 48/88/168 datasheet:
|
||
|
|
//
|
||
|
|
// SPI2X | SPR1 | SPR0 | SCK Frequency
|
||
|
|
// 1 | 0 | 0 | f_osc/2
|
||
|
|
//
|
||
|
|
// Where f_osc is the Oscillator Clock frequency
|
||
|
|
//
|
||
|
|
// This is the highest SPI clock frequency supported.
|
||
|
|
|
||
|
|
SPCR = (1<<SPE)|(1<<MSTR)|(0<<SPR1)|(0<<SPR0);
|
||
|
|
SPSR = SPSR | (1 << SPI2X);
|
||
|
|
|
||
|
|
#if 0
|
||
|
|
// This approach is not specified in the datasheet so I'm trying without.
|
||
|
|
char clr = 0;
|
||
|
|
|
||
|
|
clr=SPSR;
|
||
|
|
clr=SPDR;
|
||
|
|
delay(10);
|
||
|
|
#endif
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void SpiDevice::deselect() {
|
||
|
|
/*
|
||
|
|
|
||
|
|
Deselect the SPI device.
|
||
|
|
|
||
|
|
*/
|
||
|
|
digitalWrite(_selectPin, HIGH);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void SpiDevice::select() {
|
||
|
|
/*
|
||
|
|
|
||
|
|
Select the SPI device.
|
||
|
|
|
||
|
|
*/
|
||
|
|
digitalWrite(_selectPin, LOW);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
byte SpiDevice::transfer(volatile byte data) {
|
||
|
|
/*
|
||
|
|
|
||
|
|
Transfer byte to SPI device and return
|
||
|
|
the byte retrieved.
|
||
|
|
|
||
|
|
*/
|
||
|
|
SPDR = data; // Start the transmission
|
||
|
|
while (!(SPSR & (1<<SPIF))) {
|
||
|
|
// Wait for the end of the transmission
|
||
|
|
};
|
||
|
|
return SPDR; // Return the received byte
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void SpiDevice::transfer_bulk(const uint8_t* srcptr, unsigned long int length) {
|
||
|
|
/*
|
||
|
|
|
||
|
|
Transfer an array of bytes to the SPI device.
|
||
|
|
|
||
|
|
Discards all returned bytes.
|
||
|
|
|
||
|
|
*/
|
||
|
|
for(unsigned long int offset = 0; offset < length; offset++) {
|
||
|
|
transfer(srcptr[offset]);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|