/* =========================
* ===== Sercom UART
* =========================
*/
void SERCOM::initUART(SercomUartMode mode, SercomUartSampleRate sampleRate, uint32_t baudrate)
{
initClockNVIC();
resetUART();
//Setting the CTRLA register
sercom->USART.CTRLA.reg = SERCOM_USART_CTRLA_MODE(mode) |
SERCOM_USART_CTRLA_SAMPR(sampleRate);
//Setting the Interrupt register
sercom->USART.INTENSET.reg = SERCOM_USART_INTENSET_RXC | //Received complete
SERCOM_USART_INTENSET_ERROR; //All others errors
if ( mode == UART_INT_CLOCK )
{
uint16_t sampleRateValue;
if (sampleRate == SAMPLE_RATE_x16) {
sampleRateValue = 16;
} else {
sampleRateValue = 8;
}
// Asynchronous fractional mode (Table 24-2 in datasheet)
// BAUD = fref / (sampleRateValue * fbaud)
// (multiply by 8, to calculate fractional piece)
uint32_t baudTimes8 = (SystemCoreClock * 8) / (sampleRateValue * baudrate);
sercom->USART.BAUD.FRAC.FP = (baudTimes8 % 8);
sercom->USART.BAUD.FRAC.BAUD = (baudTimes8 / 8);
}
}
/* =========================
* ===== Sercom UART
* =========================
*/
void SERCOM::initUART(SercomUartMode mode, SercomUartSampleRate sampleRate, uint32_t baudrate)
{
#if (SAML21)
// On the SAML21, SERCOM5 is on PD0, which is a low power domain on a different bridge than the other SERCOMs.
// SERCOM5 does not support SAMPLE_RATE_x8 or SAMPLE_RATE_x3.
if (sercom == SERCOM5) {
sampleRate = SAMPLE_RATE_x16;
}
#endif
initClockNVIC();
resetUART();
//Setting the CTRLA register
sercom->USART.CTRLA.reg = SERCOM_USART_CTRLA_MODE(mode) |
SERCOM_USART_CTRLA_SAMPR(sampleRate);
//Setting the Interrupt register
sercom->USART.INTENSET.reg = SERCOM_USART_INTENSET_RXC | //Received complete
SERCOM_USART_INTENSET_ERROR; //All others errors
if ( mode == UART_INT_CLOCK )
{
uint16_t sampleRateValue;
if (sampleRate == SAMPLE_RATE_x16) {
sampleRateValue = 16;
} else {
sampleRateValue = 8;
}
#if 0
// Asynchronous arithmetic mode
// 65535 * ( 1 - sampleRateValue * baudrate / SercomClock);
// 65535 - 65535 * (sampleRateValue * baudrate / SercomClock));
// sercom->USART.BAUD.reg = 65535.0f * ( 1.0f - (float)(sampleRateValue) * (float)(baudrate) / (float)(SercomCoreClock)); // this pulls in 3KB of floating point math code
// make numerator much larger than denominator so result is integer (avoid floating point).
uint64_t numerator = ((sampleRateValue * (uint64_t)baudrate) << 32); // 32 bits of shifting ensures no loss of precision.
uint64_t ratio = divide64(numerator, SercomClock);
uint64_t scale = ((uint64_t)1 << 32) - ratio;
uint64_t baudValue = (65536 * scale) >> 32;
sercom->USART.BAUD.reg = baudValue;
#endif
// Asynchronous fractional mode (Table 24-2 in datasheet)
// BAUD = fref / (sampleRateValue * fbaud)
// (multiply by 8, to calculate fractional piece)
uint32_t baudTimes8 = (SercomClock * 8) / (sampleRateValue * baudrate);
sercom->USART.BAUD.FRAC.FP = (baudTimes8 % 8);
sercom->USART.BAUD.FRAC.BAUD = (baudTimes8 / 8);
}
/* =========================
* ===== Sercom SPI
* =========================
*/
void SERCOM::initSPI(SercomSpiTXPad mosi, SercomRXPad miso, SercomSpiCharSize charSize, SercomDataOrder dataOrder)
{
resetSPI();
initClockNVIC();
//Setting the CTRLA register
sercom->SPI.CTRLA.reg = SERCOM_SPI_CTRLA_MODE_SPI_MASTER |
SERCOM_SPI_CTRLA_DOPO(mosi) |
SERCOM_SPI_CTRLA_DIPO(miso) |
dataOrder << SERCOM_SPI_CTRLA_DORD_Pos;
//Setting the CTRLB register
sercom->SPI.CTRLB.reg = SERCOM_SPI_CTRLB_CHSIZE(charSize) |
SERCOM_SPI_CTRLB_RXEN; //Active the SPI receiver.
}
void SERCOM::initMasterWIRE( uint32_t baudrate )
{
// Initialize the peripheral clock and interruption
initClockNVIC() ;
resetWIRE() ;
// Set master mode and enable SCL Clock Stretch mode (stretch after ACK bit)
sercom->I2CM.CTRLA.reg = SERCOM_I2CM_CTRLA_MODE( I2C_MASTER_OPERATION )/* |
SERCOM_I2CM_CTRLA_SCLSM*/ ;
// Enable Smart mode and Quick Command
//sercom->I2CM.CTRLB.reg = SERCOM_I2CM_CTRLB_SMEN /*| SERCOM_I2CM_CTRLB_QCEN*/ ;
// Enable all interrupts
// sercom->I2CM.INTENSET.reg = SERCOM_I2CM_INTENSET_MB | SERCOM_I2CM_INTENSET_SB | SERCOM_I2CM_INTENSET_ERROR ;
// Synchronous arithmetic baudrate
sercom->I2CM.BAUD.bit.BAUD = SystemCoreClock / ( 2 * baudrate) - 1 ;
}
void SERCOM::initSlaveWIRE( uint8_t ucAddress )
{
// Initialize the peripheral clock and interruption
initClockNVIC() ;
resetWIRE() ;
// Set slave mode
sercom->I2CS.CTRLA.bit.MODE = I2C_SLAVE_OPERATION ;
sercom->I2CS.ADDR.reg = SERCOM_I2CS_ADDR_ADDR( ucAddress & 0x7Ful ) | // 0x7F, select only 7 bits
SERCOM_I2CS_ADDR_ADDRMASK( 0x3FFul ) ; // 0x3FF all bits set
// Set the interrupt register
sercom->I2CS.INTENSET.reg = SERCOM_I2CS_INTENSET_PREC | // Stop
SERCOM_I2CS_INTENSET_AMATCH | // Address Match
SERCOM_I2CS_INTENSET_DRDY ; // Data Ready
while ( sercom->I2CM.SYNCBUSY.bit.SYSOP != 0 )
{
// Wait the SYSOP bit from SYNCBUSY to come back to 0
}
}
/* =========================
* ===== Sercom UART
* =========================
*/
void SERCOM::initUART(SercomUartMode mode, SercomUartSampleRate sampleRate, uint32_t baudrate)
{
initClockNVIC();
resetUART();
//Setting the CTRLA register
sercom->USART.CTRLA.reg = SERCOM_USART_CTRLA_MODE(mode) |
SERCOM_USART_CTRLA_SAMPR(sampleRate);
//Setting the Interrupt register
sercom->USART.INTENSET.reg = SERCOM_USART_INTENSET_RXC | //Received complete
SERCOM_USART_INTENSET_ERROR; //All others errors
if ( mode == UART_INT_CLOCK )
{
uint16_t sampleRateValue ;
if ( sampleRate == SAMPLE_RATE_x16 )
{
sampleRateValue = 16 ;
}
else
{
if ( sampleRate == SAMPLE_RATE_x8 )
{
sampleRateValue = 8 ;
}
else
{
sampleRateValue = 3 ;
}
}
// Asynchronous arithmetic mode
// 65535 * ( 1 - sampleRateValue * baudrate / SystemCoreClock);
// 65535 - 65535 * (sampleRateValue * baudrate / SystemCoreClock));
sercom->USART.BAUD.reg = 65535.0f * ( 1.0f - (float)(sampleRateValue) * (float)(baudrate) / (float)(SystemCoreClock));
}
}
