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Optimize SPI transfers #180

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Merged
merged 1 commit into from
Nov 17, 2016
Merged

Optimize SPI transfers #180

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17 changes: 2 additions & 15 deletions cores/arduino/SERCOM.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -300,24 +300,11 @@ void SERCOM::setClockModeSPI(SercomSpiClockMode clockMode)
enableSPI();
}

void SERCOM::writeDataSPI(uint8_t data)
uint8_t SERCOM::transferDataSPI(uint8_t data)
{
while( sercom->SPI.INTFLAG.bit.DRE == 0 )
{
// Waiting Data Registry Empty
}

sercom->SPI.DATA.bit.DATA = data; // Writing data into Data register

while( sercom->SPI.INTFLAG.bit.TXC == 0 || sercom->SPI.INTFLAG.bit.DRE == 0 )
{
// Waiting Complete Transmission
}
}

uint16_t SERCOM::readDataSPI()
{
while( sercom->SPI.INTFLAG.bit.DRE == 0 || sercom->SPI.INTFLAG.bit.RXC == 0 )
while( sercom->SPI.INTFLAG.bit.RXC == 0 )
{
// Waiting Complete Reception
}
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3 changes: 1 addition & 2 deletions cores/arduino/SERCOM.h
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Original file line number Diff line number Diff line change
Expand Up @@ -175,8 +175,7 @@ class SERCOM
SercomDataOrder getDataOrderSPI( void ) ;
void setBaudrateSPI(uint8_t divider) ;
void setClockModeSPI(SercomSpiClockMode clockMode) ;
void writeDataSPI(uint8_t data) ;
uint16_t readDataSPI( void ) ;
uint8_t transferDataSPI(uint8_t data) ;
bool isBufferOverflowErrorSPI( void ) ;
bool isDataRegisterEmptySPI( void ) ;
bool isTransmitCompleteSPI( void ) ;
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15 changes: 10 additions & 5 deletions libraries/SPI/SPI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -187,11 +187,7 @@ void SPIClass::setClockDivider(uint8_t div)

byte SPIClass::transfer(uint8_t data)
{
// Writing the data
_p_sercom->writeDataSPI(data);

// Read data
return _p_sercom->readDataSPI() & 0xFF;
return _p_sercom->transferDataSPI(data);
}

uint16_t SPIClass::transfer16(uint16_t data) {
Expand All @@ -210,6 +206,15 @@ uint16_t SPIClass::transfer16(uint16_t data) {
return t.val;
}

void SPIClass::transfer(void *buf, size_t count)
{
uint8_t *buffer = reinterpret_cast<uint8_t *>(buf);
for (size_t i=0; i<count; i++) {
*buffer = transfer(*buffer);
buffer++;
}
}

void SPIClass::attachInterrupt() {
// Should be enableInterrupt()
}
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10 changes: 1 addition & 9 deletions libraries/SPI/SPI.h
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Expand Up @@ -96,7 +96,7 @@ class SPIClass {

byte transfer(uint8_t data);
uint16_t transfer16(uint16_t data);
inline void transfer(void *buf, size_t count);
void transfer(void *buf, size_t count);

// Transaction Functions
void usingInterrupt(int interruptNumber);
Expand Down Expand Up @@ -132,14 +132,6 @@ class SPIClass {
uint32_t interruptMask;
};

void SPIClass::transfer(void *buf, size_t count)
{
// TODO: Optimize for faster block-transfer
uint8_t *buffer = reinterpret_cast<uint8_t *>(buf);
for (size_t i=0; i<count; i++)
buffer[i] = transfer(buffer[i]);
}

#if SPI_INTERFACES_COUNT > 0
extern SPIClass SPI;
#endif
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