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Fix SPI::setClockDivider implementation #379

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Merged
merged 1 commit into from
Dec 21, 2018
Merged

Fix SPI::setClockDivider implementation #379

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34 changes: 8 additions & 26 deletions libraries/SPI/src/SPI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -220,16 +220,10 @@ void SPIClass::setDataMode(uint8_t _pin, uint8_t _mode)

/**
* @brief Deprecated function.
* Configure the clock speed: 125kHz to 8MHz.
* Configure the clock speed
* @param _pin: CS pin associated to a configuration (optional).
* @param _divider: can be one of the following parameters:
* SPI_CLOCK_DIV2 (8MHz)
* SPI_CLOCK_DIV4 (4MHz)
* SPI_CLOCK_DIV8 (2MHz)
* SPI_CLOCK_DIV16 (1MHz)
* SPI_CLOCK_DIV32 (500kHz)
* SPI_CLOCK_DIV64 (250kHz)
* SPI_CLOCK_DIV128 (125kHz)
* @param _divider: the SPI clock can be divided by values from 1 to 255.
* If 0, default SPI speed is used.
*/
void SPIClass::setClockDivider(uint8_t _pin, uint8_t _divider)
{
Expand All @@ -240,23 +234,11 @@ void SPIClass::setClockDivider(uint8_t _pin, uint8_t _divider)
if(idx >= NB_SPI_SETTINGS) {
return;
}

/* Get clk freq of the SPI instance */
uint32_t spiClkFreq = spi_getClkFreq(&_spi);

switch(_divider) {
case (SPI_CLOCK_DIV2) :
case (SPI_CLOCK_DIV4) :
case (SPI_CLOCK_DIV8) :
case (SPI_CLOCK_DIV16) :
case (SPI_CLOCK_DIV32) :
case (SPI_CLOCK_DIV64) :
case (SPI_CLOCK_DIV128) :
spiSettings[idx].clk = spiClkFreq/_divider;
break;
default:
spiSettings[idx].clk = SPI_SPEED_CLOCK_DEFAULT;
break;
if (_divider == 0) {
spiSettings[idx].clk = SPI_SPEED_CLOCK_DEFAULT;
} else {
/* Get clk freq of the SPI instance and compute it */
spiSettings[idx].clk = spi_getClkFreq(&_spi)/_divider;
}

spi_init(&_spi, spiSettings[idx].clk,
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7 changes: 4 additions & 3 deletions libraries/SPI/src/SPI.h
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Expand Up @@ -22,9 +22,10 @@
// - SPISetting(clock, bitOrder, dataMode)
#define SPI_HAS_TRANSACTION 1

// For compatibility with sketches designed for AVR @ 16 MHz
// need to go from 64MHz to 16 (/4)
// This function should not be used in new projects.
// Compatibility with sketches designed for AVR @ 16 MHz could not
// be ensured as SPI frequency depends of system clock configuration.
// user have to use appropriate divider for the SPI clock
// This function should not be used in new project.
// Use SPISettings with SPI.beginTransaction() to configure SPI parameters.
#define SPI_CLOCK_DIV2 2
#define SPI_CLOCK_DIV4 4
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