/**
* @brief UART initialization.
* @details This function must be invoked with interrupts disabled.
*
* @param[in] sdp pointer to a @p SerialDriver object
* @param[in] config the architecture-dependent serial driver configuration
*/
static void uart_init(SerialDriver *sdp, const SerialConfig *config) {
#if SAMA_SERIAL_USE_UART && SAMA_SERIAL_USE_FLEXCOM
if (sdp->uart != NULL)
#endif /* SAMA_SERIAL_USE_UART && SAMA_SERIAL_USE_FLEXCOM */
#if SAMA_SERIAL_USE_UART
{
Uart *u = sdp->uart;
/* Disabling write protection */
sdDisableWP(u);
/* Baud rate setting.*/
u->UART_BRGR = UART_BRGR_CD(sdp->clock / (16 * config->speed));
u->UART_CR = config->cr;
u->UART_MR = config->mr;
u->UART_IER = UART_IER_RXRDY;
/* Clearing error status bit */
u->UART_CR |= UART_CR_RSTSTA;
/* Enabling Tx and Rx */
u->UART_CR |= UART_CR_RXEN | UART_CR_TXEN;
/* Enabling write protection */
sdEnableWP(u);
}
#endif /* SAMA_SERIAL_USE_UART */
#if SAMA_SERIAL_USE_UART && SAMA_SERIAL_USE_FLEXCOM
else if (sdp->usart != NULL)
#endif /* SAMA_SERIAL_USE_UART && SAMA_SERIAL_USE_FLEXCOM */
#if SAMA_SERIAL_USE_FLEXCOM
{
Flexcom *fl = sdp->flexcom;
Usart *us = sdp->usart;
/* Disabling write protection */
sdFlexDisableWP(us)
/* Enabling USART on FLEXCOM */
fl->FLEX_MR = FLEX_MR_OPMODE_USART;
/* Baud rate setting (OVER = 0 and SYNC = 0)*/
us->US_BRGR = US_BRGR_CD(sdp->clock / (16 * config->speed));
us->US_CR = config->cr;
us->US_MR = config->mr;
us->US_IER = US_IER_RXRDY;
/* Clearing status bit */
us->US_CR |= US_CR_RSTSTA;
/* Enabling Tx and Rx */
us->US_CR |= US_CR_RXEN | US_CR_TXEN;
/* Enabling write protection */
sdFlexEnableWP(us)
}
void uart_init(const uart_settings_t *settings) {
/*
* reset receiver, transmitter and status bits,
* disable receiver and transmitter
*/
UART->UART_CR = UART_CR_RSTRX | UART_CR_RSTTX | UART_CR_RSTSTA |
UART_CR_RXDIS | UART_CR_TXDIS;
// configure baud rate
UART->UART_BRGR = UART_BRGR_CD(settings->baud_rate);
// configure mode
UART->UART_MR = UART_MR_CHMODE(settings->ch_mode);
// enable receiver and transmitter
UART->UART_CR = UART_CR_RXEN | UART_CR_TXEN;
}
static int baudrate_set(Uart *const uart, u32_t baudrate,
u32_t mck_freq_hz)
{
u32_t divisor;
__ASSERT(baudrate,
"baud rate has to be bigger than 0");
__ASSERT(mck_freq_hz/16U >= baudrate,
"MCK frequency is too small to set required baud rate");
divisor = mck_freq_hz / 16U / baudrate;
if (divisor > 0xFFFF) {
return -EINVAL;
}
uart->UART_BRGR = UART_BRGR_CD(divisor);
return 0;
}
