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rt-thread-official/bsp/efm32/Libraries/emlib/src/em_usart.c

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/***************************************************************************//**
* @file
* @brief Universal synchronous/asynchronous receiver/transmitter (USART/UART)
* Peripheral API
* @author Energy Micro AS
* @version 3.0.0
*******************************************************************************
* @section License
* <b>(C) Copyright 2012 Energy Micro AS, http://www.energymicro.com</b>
*******************************************************************************
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*
* DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Energy Micro AS has no
* obligation to support this Software. Energy Micro AS is providing the
* Software "AS IS", with no express or implied warranties of any kind,
* including, but not limited to, any implied warranties of merchantability
* or fitness for any particular purpose or warranties against infringement
* of any proprietary rights of a third party.
*
* Energy Micro AS will not be liable for any consequential, incidental, or
* special damages, or any other relief, or for any claim by any third party,
* arising from your use of this Software.
*
******************************************************************************/
#include "em_usart.h"
#include "em_cmu.h"
#include "em_assert.h"
/***************************************************************************//**
* @addtogroup EM_Library
* @{
******************************************************************************/
/***************************************************************************//**
* @addtogroup USART
* @brief Universal Synchronous/Asynchronous Receiver/Transmitter
* Peripheral API
* @{
******************************************************************************/
/*******************************************************************************
******************************* DEFINES ***********************************
******************************************************************************/
/** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
/** Validation of USART register block pointer reference for assert statements. */
#if (USART_COUNT == 1)
#define USART_REF_VALID(ref) ((ref) == USART0)
#elif (USART_COUNT == 2)
#define USART_REF_VALID(ref) (((ref) == USART0) || ((ref) == USART1))
#elif (USART_COUNT == 3)
#define USART_REF_VALID(ref) (((ref) == USART0) || ((ref) == USART1) || \
((ref) == USART2))
#elif (USART_COUNT == 4)
#define USART_REF_VALID(ref) (((ref) == USART0) || ((ref) == USART1) || \
((ref) == USART2) || ((ref) == USART3))
#else
#error Undefined number of USARTs.
#endif
#define USART_IRDA_VALID(ref) ((ref) == USART0)
#if defined(_EFM32_TINY_FAMILY)
#define USART_I2S_VALID(ref) ((ref) == USART1)
#endif
#if defined(_EFM32_GIANT_FAMILY)
#define USART_I2S_VALID(ref) (((ref) == USART1) || ((ref) == USART2))
#endif
#if (UART_COUNT == 1)
#define UART_REF_VALID(ref) ((ref)==UART0)
#elif (UART_COUNT == 2)
#define UART_REF_VALID(ref) (((ref)==UART0) || ((ref)==UART1))
#else
#define UART_REF_VALID(ref) (0)
#endif
/** @endcond */
/*******************************************************************************
************************** GLOBAL FUNCTIONS *******************************
******************************************************************************/
/***************************************************************************//**
* @brief
* Configure USART/UART operating in asynchronous mode to use a given
* baudrate (or as close as possible to specified baudrate).
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @param[in] refFreq
* USART/UART reference clock frequency in Hz that will be used. If set to 0,
* the currently configured reference clock is assumed.
*
* @param[in] baudrate
* Baudrate to try to achieve for USART/UART.
*
* @param[in] ovs
* Oversampling to be used. Normal is 16x oversampling, but lower oversampling
* may be used to achieve higher rates or better baudrate accuracy in some
* cases. Notice that lower oversampling frequency makes channel more
* vulnerable to bit faults during reception due to clock inaccuracies
* compared to link partner.
******************************************************************************/
void USART_BaudrateAsyncSet(USART_TypeDef *usart,
uint32_t refFreq,
uint32_t baudrate,
USART_OVS_TypeDef ovs)
{
uint32_t clkdiv;
uint32_t oversample;
/* Inhibit divide by 0 */
EFM_ASSERT(baudrate);
/*
* We want to use integer division to avoid forcing in float division
* utils, and yet keep rounding effect errors to a minimum.
*
* CLKDIV in asynchronous mode is given by:
*
* CLKDIV = 256 * (fHFPERCLK/(oversample * br) - 1)
* or
* CLKDIV = (256 * fHFPERCLK)/(oversample * br) - 256
*
* The basic problem with integer division in the above formula is that
* the dividend (256 * fHFPERCLK) may become higher than max 32 bit
* integer. Yet, we want to evaluate dividend first before dividing in
* order to get as small rounding effects as possible. We do not want
* to make too harsh restrictions on max fHFPERCLK value either.
*
* One can possibly factorize 256 and oversample/br. However,
* since the last 6 bits of CLKDIV are don't care, we can base our
* integer arithmetic on the below formula
*
* CLKDIV / 64 = (4 * fHFPERCLK)/(oversample * br) - 4
*
* and calculate 1/64 of CLKDIV first. This allows for fHFPERCLK
* up to 1GHz without overflowing a 32 bit value!
*/
/* HFPERCLK used to clock all USART/UART peripheral modules */
if (!refFreq)
{
refFreq = CMU_ClockFreqGet(cmuClock_HFPER);
}
/* Map oversampling */
switch (ovs)
{
case USART_CTRL_OVS_X16:
EFM_ASSERT(baudrate <= (refFreq / 16));
oversample = 16;
break;
case USART_CTRL_OVS_X8:
EFM_ASSERT(baudrate <= (refFreq / 8));
oversample = 8;
break;
case USART_CTRL_OVS_X6:
EFM_ASSERT(baudrate <= (refFreq / 6));
oversample = 6;
break;
case USART_CTRL_OVS_X4:
EFM_ASSERT(baudrate <= (refFreq / 4));
oversample = 4;
break;
default:
/* Invalid input */
EFM_ASSERT(0);
return;
}
/* Calculate and set CLKDIV with fractional bits */
clkdiv = 4 * refFreq + (oversample * baudrate) / 2;
clkdiv /= (oversample * baudrate);
clkdiv -= 4;
clkdiv *= 64;
usart->CTRL &= ~_USART_CTRL_OVS_MASK;
usart->CTRL |= ovs;
usart->CLKDIV = clkdiv;
}
/***************************************************************************//**
* @brief
* Calculate baudrate for USART/UART given reference frequency, clock division
* and oversampling rate (if async mode).
*
* @details
* This function returns the baudrate that a USART/UART module will use if
* configured with the given frequency, clock divisor and mode. Notice that
* this function will not use actual HW configuration. It can be used
* to determinate if a given configuration is sufficiently accurate for the
* application.
*
* @param[in] refFreq
* USART/UART HF peripheral frequency used.
*
* @param[in] clkdiv
* Clock division factor to be used.
*
* @param[in] syncmode
* @li true - synchronous mode operation.
* @li false - asynchronous mode operation.
*
* @param[in] ovs
* Oversampling used if asynchronous mode. Not used if @p syncmode is true.
*
* @return
* Baudrate with given settings.
******************************************************************************/
uint32_t USART_BaudrateCalc(uint32_t refFreq,
uint32_t clkdiv,
bool syncmode,
USART_OVS_TypeDef ovs)
{
uint32_t oversample;
uint32_t divisor;
uint32_t factor;
uint32_t remainder;
uint32_t quotient;
uint32_t br;
/* Mask out unused bits */
clkdiv &= _USART_CLKDIV_MASK;
/* We want to use integer division to avoid forcing in float division */
/* utils, and yet keep rounding effect errors to a minimum. */
/* Baudrate calculation depends on if synchronous or asynchronous mode */
if (syncmode)
{
/*
* Baudrate is given by:
*
* br = fHFPERCLK/(2 * (1 + (CLKDIV / 256)))
*
* which can be rewritten to
*
* br = (128 * fHFPERCLK)/(256 + CLKDIV)
*/
oversample = 1; /* Not used in sync mode, ie 1 */
factor = 128;
}
else
{
/*
* Baudrate in asynchronous mode is given by:
*
* br = fHFPERCLK/(oversample * (1 + (CLKDIV / 256)))
*
* which can be rewritten to
*
* br = (256 * fHFPERCLK)/(oversample * (256 + CLKDIV))
*
* First of all we can reduce the 256 factor of the dividend with
* (part of) oversample part of the divisor.
*/
switch (ovs)
{
case USART_CTRL_OVS_X16:
oversample = 1;
factor = 256 / 16;
break;
case USART_CTRL_OVS_X8:
oversample = 1;
factor = 256 / 8;
break;
case USART_CTRL_OVS_X6:
oversample = 3;
factor = 256 / 2;
break;
default:
oversample = 1;
factor = 256 / 4;
break;
}
}
/*
* The basic problem with integer division in the above formula is that
* the dividend (factor * fHFPERCLK) may become higher than max 32 bit
* integer. Yet we want to evaluate dividend first before dividing in
* order to get as small rounding effects as possible. We do not want
* to make too harsh restrictions on max fHFPERCLK value either.
*
* For division a/b, we can write
*
* a = qb + r
*
* where q is the quotient and r is the remainder, both integers.
*
* The orignal baudrate formula can be rewritten as
*
* br = xa / b = x(qb + r)/b = xq + xr/b
*
* where x is 'factor', a is 'refFreq' and b is 'divisor', referring to
* variable names.
*/
/* Divisor will never exceed max 32 bit value since clkdiv <= 0x1fffc0 */
/* and 'oversample' has been reduced to <= 3. */
divisor = oversample * (256 + clkdiv);
quotient = refFreq / divisor;
remainder = refFreq % divisor;
/* factor <= 128 and since divisor >= 256, the below cannot exceed max */
/* 32 bit value. */
br = factor * quotient;
/*
* factor <= 128 and remainder < (oversample*(256 + clkdiv)), which
* means dividend (factor * remainder) worst case is
* 128*(3 * (256 + 0x1fffc0)) = 0x30012000.
*/
br += (factor * remainder) / divisor;
return br;
}
/***************************************************************************//**
* @brief
* Get current baudrate for USART/UART.
*
* @details
* This function returns the actual baudrate (not considering oscillator
* inaccuracies) used by a USART/UART peripheral.
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @return
* Current baudrate.
******************************************************************************/
uint32_t USART_BaudrateGet(USART_TypeDef *usart)
{
uint32_t freq;
USART_OVS_TypeDef ovs;
bool syncmode;
if (usart->CTRL & USART_CTRL_SYNC)
{
syncmode = true;
}
else
{
syncmode = false;
}
/* HFPERCLK used to clock all USART/UART peripheral modules */
freq = CMU_ClockFreqGet(cmuClock_HFPER);
ovs = (USART_OVS_TypeDef)(usart->CTRL & _USART_CTRL_OVS_MASK);
return USART_BaudrateCalc(freq, usart->CLKDIV, syncmode, ovs);
}
/***************************************************************************//**
* @brief
* Configure USART operating in synchronous mode to use a given baudrate
* (or as close as possible to specified baudrate).
*
* @details
* The configuration will be set to use a baudrate <= the specified baudrate
* in order to ensure that the baudrate does not exceed the specified value.
*
* Fractional clock division is suppressed, although the HW design allows it.
* It could cause half clock cycles to exceed specified limit, and thus
* potentially violate specifications for the slave device. In some special
* situations fractional clock division may be useful even in synchronous
* mode, but in those cases it must be directly adjusted, possibly assisted
* by USART_BaudrateCalc():
*
* @param[in] usart
* Pointer to USART peripheral register block. (Cannot be used on UART
* modules.)
*
* @param[in] refFreq
* USART reference clock frequency in Hz that will be used. If set to 0,
* the currently configured reference clock is assumed.
*
* @param[in] baudrate
* Baudrate to try to achieve for USART.
******************************************************************************/
void USART_BaudrateSyncSet(USART_TypeDef *usart, uint32_t refFreq, uint32_t baudrate)
{
uint32_t clkdiv;
/* Inhibit divide by 0 */
EFM_ASSERT(baudrate);
/*
* We want to use integer division to avoid forcing in float division
* utils, and yet keep rounding effect errors to a minimum.
*
* CLKDIV in synchronous mode is given by:
*
* CLKDIV = 256 * (fHFPERCLK/(2 * br) - 1)
* or
* CLKDIV = (256 * fHFPERCLK)/(2 * br) - 256 = (128 * fHFPERCLK)/br - 256
*
* The basic problem with integer division in the above formula is that
* the dividend (128 * fHFPERCLK) may become higher than max 32 bit
* integer. Yet, we want to evaluate dividend first before dividing in
* order to get as small rounding effects as possible. We do not want
* to make too harsh restrictions on max fHFPERCLK value either.
*
* One can possibly factorize 128 and br. However, since the last
* 6 bits of CLKDIV are don't care, we can base our integer arithmetic
* on the below formula without loosing any extra precision:
*
* CLKDIV / 64 = (2 * fHFPERCLK)/br - 4
*
* and calculate 1/64 of CLKDIV first. This allows for fHFPERCLK
* up to 2GHz without overflowing a 32 bit value!
*/
/* HFPERCLK used to clock all USART/UART peripheral modules */
if (!refFreq)
{
refFreq = CMU_ClockFreqGet(cmuClock_HFPER);
}
/* Calculate and set CLKDIV with fractional bits */
clkdiv = 2 * refFreq;
clkdiv += baudrate - 1;
clkdiv /= baudrate;
clkdiv -= 4;
clkdiv *= 64;
/* Make sure we don't use fractional bits by rounding CLKDIV */
/* up (and thus reducing baudrate, not increasing baudrate above */
/* specified value). */
clkdiv += 0xc0;
clkdiv &= 0xffffff00;
/* Verify that resulting clock divider is within limits */
EFM_ASSERT(clkdiv <= _USART_CLKDIV_MASK);
/* If EFM_ASSERT is not enabled, make sure we don't write to reserved bits */
clkdiv &= _USART_CLKDIV_DIV_MASK;
usart->CLKDIV = clkdiv;
}
/***************************************************************************//**
* @brief
* Enable/disable USART/UART receiver and/or transmitter.
*
* @details
* Notice that this function does not do any configuration. Enabling should
* normally be done after initialization is done (if not enabled as part
* of init).
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @param[in] enable
* Select status for receiver/transmitter.
******************************************************************************/
void USART_Enable(USART_TypeDef *usart, USART_Enable_TypeDef enable)
{
uint32_t tmp;
/* Make sure the module exists on the selected chip */
EFM_ASSERT(USART_REF_VALID(usart)||(UART_REF_VALID(usart)));
/* Disable as specified */
tmp = ~((uint32_t)(enable));
tmp &= _USART_CMD_RXEN_MASK | _USART_CMD_TXEN_MASK;
usart->CMD = tmp << 1;
/* Enable as specified */
usart->CMD = (uint32_t)(enable);
}
/***************************************************************************//**
* @brief
* Init USART/UART for normal asynchronous mode.
*
* @details
* This function will configure basic settings in order to operate in normal
* asynchronous mode.
*
* Special control setup not covered by this function must be done after
* using this function by direct modification of the CTRL register.
*
* Notice that pins used by the USART/UART module must be properly configured
* by the user explicitly, in order for the USART/UART to work as intended.
* (When configuring pins, one should remember to consider the sequence of
* configuration, in order to avoid unintended pulses/glitches on output
* pins.)
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @param[in] init
* Pointer to initialization structure used to configure basic async setup.
******************************************************************************/
void USART_InitAsync(USART_TypeDef *usart, const USART_InitAsync_TypeDef *init)
{
/* Make sure the module exists on the selected chip */
EFM_ASSERT(USART_REF_VALID(usart)||UART_REF_VALID(usart));
/* Init USART registers to HW reset state. */
USART_Reset(usart);
#if defined(_EFM32_GIANT_FAMILY) || defined(_EFM32_TINY_FAMILY)
/* Disable majority vote if specified. */
if (init->mvdis)
{
usart->CTRL |= USART_CTRL_MVDIS;
}
/* Configure PRS input mode. */
if (init->prsRxEnable)
{
usart->INPUT = (uint32_t)init->prsRxCh | USART_INPUT_RXPRS;
}
#endif
/* Configure databits, stopbits and parity */
usart->FRAME = (uint32_t)(init->databits) |
(uint32_t)(init->stopbits) |
(uint32_t)(init->parity);
/* Configure baudrate */
USART_BaudrateAsyncSet(usart, init->refFreq, init->baudrate, init->oversampling);
/* Finally enable (as specified) */
usart->CMD = (uint32_t)(init->enable);
}
/***************************************************************************//**
* @brief
* Init USART for synchronous mode.
*
* @details
* This function will configure basic settings in order to operate in
* synchronous mode.
*
* Special control setup not covered by this function must be done after
* using this function by direct modification of the CTRL register.
*
* Notice that pins used by the USART module must be properly configured
* by the user explicitly, in order for the USART to work as intended.
* (When configuring pins, one should remember to consider the sequence of
* configuration, in order to avoid unintended pulses/glitches on output
* pins.)
*
* @param[in] usart
* Pointer to USART peripheral register block. (UART does not support this
* mode.)
*
* @param[in] init
* Pointer to initialization structure used to configure basic async setup.
******************************************************************************/
void USART_InitSync(USART_TypeDef *usart, const USART_InitSync_TypeDef *init)
{
/* Make sure the module exists on the selected chip */
EFM_ASSERT(USART_REF_VALID(usart));
/* Init USART registers to HW reset state. */
USART_Reset(usart);
/* Set bits for synchronous mode */
usart->CTRL |= (USART_CTRL_SYNC) |
((uint32_t)init->clockMode) |
(init->msbf ? USART_CTRL_MSBF : 0);
#if defined(_EFM32_GIANT_FAMILY) || defined(_EFM32_TINY_FAMILY)
usart->CTRL |= (init->prsRxEnable ? USART_INPUT_RXPRS : 0) |
(init->autoTx ? USART_CTRL_AUTOTX : 0);
#endif
/* Configure databits, leave stopbits and parity at reset default (not used) */
usart->FRAME = ((uint32_t)(init->databits)) |
(USART_FRAME_STOPBITS_DEFAULT) |
(USART_FRAME_PARITY_DEFAULT);
/* Configure baudrate */
USART_BaudrateSyncSet(usart, init->refFreq, init->baudrate);
/* Finally enable (as specified) */
if (init->master)
{
usart->CMD = USART_CMD_MASTEREN;
}
usart->CMD = (uint32_t)(init->enable);
}
/***************************************************************************//**
* @brief
* Init USART0 for asynchronous IrDA mode.
*
* @details
* This function will configure basic settings in order to operate in
* asynchronous IrDA mode.
*
* Special control setup not covered by this function must be done after
* using this function by direct modification of the CTRL and IRCTRL
* registers.
*
* Notice that pins used by the USART/UART module must be properly configured
* by the user explicitly, in order for the USART/UART to work as intended.
* (When configuring pins, one should remember to consider the sequence of
* configuration, in order to avoid unintended pulses/glitches on output
* pins.)
*
* @param[in] init
* Pointer to initialization structure used to configure async IrDA setup.
*
* @note
* This function only applies to USART0 as IrDA is not supported on the other
* USART modules.
*
******************************************************************************/
void USART_InitIrDA(const USART_InitIrDA_TypeDef *init)
{
/* Init USART0 as async device */
USART_InitAsync(USART0, &(init->async));
/* Set IrDA modulation to RZI (return-to-zero-inverted) */
USART0->CTRL |= USART_CTRL_TXINV;
/* Invert Rx signal before demodulator if enabled */
if (init->irRxInv)
{
USART0->CTRL |= USART_CTRL_RXINV;
}
/* Configure IrDA */
USART0->IRCTRL |= (uint32_t)init->irPw |
(uint32_t)init->irPrsSel |
((uint32_t)init->irFilt << _USART_IRCTRL_IRFILT_SHIFT) |
((uint32_t)init->irPrsEn << _USART_IRCTRL_IRPRSEN_SHIFT);
/* Enable IrDA */
USART0->IRCTRL |= USART_IRCTRL_IREN;
}
#if defined(_EFM32_GIANT_FAMILY) || defined(_EFM32_TINY_FAMILY)
/***************************************************************************//**
* @brief
* Init USART for I2S mode.
*
* @details
* This function will configure basic settings in order to operate in I2S
* mode.
*
* Special control setup not covered by this function must be done after
* using this function by direct modification of the CTRL and I2SCTRL
* registers.
*
* Notice that pins used by the USART module must be properly configured
* by the user explicitly, in order for the USART to work as intended.
* (When configuring pins, one should remember to consider the sequence of
* configuration, in order to avoid unintended pulses/glitches on output
* pins.)
*
* @param[in] usart
* Pointer to USART peripheral register block. (UART does not support this
* mode.)
*
* @param[in] init
* Pointer to initialization structure used to configure basic I2S setup.
*
* @note
* This function does not apply to all USART's. Refer to chip manuals.
*
******************************************************************************/
void USART_InitI2s(USART_TypeDef *usart, USART_InitI2s_TypeDef *init)
{
USART_Enable_TypeDef enable;
/* Make sure the module exists on the selected chip */
EFM_ASSERT(USART_I2S_VALID(usart));
/* Override the enable setting. */
enable = init->sync.enable;
init->sync.enable = usartDisable;
/* Init USART as a sync device. */
USART_InitSync(usart, &init->sync);
/* Configure and enable I2CCTRL register acording to selected mode. */
usart->I2SCTRL = ((uint32_t)init->format) |
((uint32_t)init->justify) |
(init->delay ? USART_I2SCTRL_DELAY : 0) |
(init->dmaSplit ? USART_I2SCTRL_DMASPLIT : 0) |
(init->mono ? USART_I2SCTRL_MONO : 0) |
(USART_I2SCTRL_EN);
if (enable != usartDisable)
{
USART_Enable(usart, enable);
}
}
/***************************************************************************//**
* @brief
* Initialize automatic transmissions using PRS channel as trigger
* @note
* Initialize USART with USART_Init() before setting up PRS configuration
*
* @param[in] usart Pointer to USART to configure
* @param[in] init Pointer to initialization structure
******************************************************************************/
void USART_InitPrsTrigger(USART_TypeDef *usart, const USART_PrsTriggerInit_TypeDef *init)
{
uint32_t trigctrl;
/* Clear values that will be reconfigured */
trigctrl = usart->TRIGCTRL & ~(_USART_TRIGCTRL_RXTEN_MASK|
_USART_TRIGCTRL_TXTEN_MASK|
#if defined(_EFM32_GIANT_FAMILY)
_USART_TRIGCTRL_AUTOTXTEN_MASK|
#endif
_USART_TRIGCTRL_TSEL_MASK);
#if defined(_EFM32_GIANT_FAMILY)
if(init->autoTxTriggerEnable)
{
trigctrl |= USART_TRIGCTRL_AUTOTXTEN;
}
#endif
if(init->txTriggerEnable)
{
trigctrl |= USART_TRIGCTRL_TXTEN;
}
if(init->rxTriggerEnable)
{
trigctrl |= USART_TRIGCTRL_RXTEN;
}
trigctrl |= init->prsTriggerChannel;
/* Enable new configuration */
usart->TRIGCTRL = trigctrl;
}
#endif
/***************************************************************************//**
* @brief
* Reset USART/UART to same state as after a HW reset.
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
******************************************************************************/
void USART_Reset(USART_TypeDef *usart)
{
/* Make sure the module exists on the selected chip */
EFM_ASSERT(USART_REF_VALID(usart)||UART_REF_VALID(usart));
/* Make sure disabled first, before resetting other registers */
usart->CMD = USART_CMD_RXDIS | USART_CMD_TXDIS | USART_CMD_MASTERDIS |
USART_CMD_RXBLOCKDIS | USART_CMD_TXTRIDIS | USART_CMD_CLEARTX | USART_CMD_CLEARRX;
usart->CTRL = _USART_CTRL_RESETVALUE;
usart->FRAME = _USART_FRAME_RESETVALUE;
usart->TRIGCTRL = _USART_TRIGCTRL_RESETVALUE;
usart->CLKDIV = _USART_CLKDIV_RESETVALUE;
usart->IEN = _USART_IEN_RESETVALUE;
usart->IFC = _USART_IFC_MASK;
usart->ROUTE = _USART_ROUTE_RESETVALUE;
if (USART_IRDA_VALID(usart))
{
usart->IRCTRL = _USART_IRCTRL_RESETVALUE;
}
#if defined(_EFM32_GIANT_FAMILY) || defined(_EFM32_TINY_FAMILY)
usart->INPUT = _USART_INPUT_RESETVALUE;
if (USART_I2S_VALID(usart))
{
usart->I2SCTRL = _USART_I2SCTRL_RESETVALUE;
}
#endif
/* Do not reset route register, setting should be done independently */
}
/***************************************************************************//**
* @brief
* Receive one 4-8 bit frame, (or part of 10-16 bit frame).
*
* @details
* This function is normally used to receive one frame when operating with
* frame length 4-8 bits. Please refer to USART_RxExt() for reception of
* 9 bit frames.
*
* Notice that possible parity/stop bits in asynchronous mode are not
* considered part of specified frame bit length.
*
* @note
* This function will stall if buffer is empty, until data is received.
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @return
* Data received.
******************************************************************************/
uint8_t USART_Rx(USART_TypeDef *usart)
{
while (!(usart->STATUS & USART_STATUS_RXDATAV))
;
return (uint8_t)(usart->RXDATA);
}
/***************************************************************************//**
* @brief
* Receive two 4-8 bit frames, or one 10-16 bit frame.
*
* @details
* This function is normally used to receive one frame when operating with
* frame length 10-16 bits. Please refer to USART_RxDoubleExt() for reception
* of two 9 bit frames.
*
* Notice that possible parity/stop bits in asynchronous mode are not
* considered part of specified frame bit length.
*
* @note
* This function will stall if buffer is empty, until data is received.
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @return
* Data received.
******************************************************************************/
uint16_t USART_RxDouble(USART_TypeDef *usart)
{
while (!(usart->STATUS & USART_STATUS_RXFULL))
;
return (uint16_t)(usart->RXDOUBLE);
}
/***************************************************************************//**
* @brief
* Receive two 4-9 bit frames, or one 10-16 bit frame with extended
* information.
*
* @details
* This function is normally used to receive one frame when operating with
* frame length 10-16 bits and additional RX status information is required.
*
* Notice that possible parity/stop bits in asynchronous mode are not
* considered part of specified frame bit length.
*
* @note
* This function will stall if buffer is empty, until data is received.
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @return
* Data received.
******************************************************************************/
uint32_t USART_RxDoubleExt(USART_TypeDef *usart)
{
while (!(usart->STATUS & USART_STATUS_RXFULL))
;
return usart->RXDOUBLEX;
}
/***************************************************************************//**
* @brief
* Receive one 4-9 bit frame, (or part of 10-16 bit frame) with extended
* information.
*
* @details
* This function is normally used to receive one frame when operating with
* frame length 4-9 bits and additional RX status information is required.
*
* Notice that possible parity/stop bits in asynchronous mode are not
* considered part of specified frame bit length.
*
* @note
* This function will stall if buffer is empty, until data is received.
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @return
* Data received.
******************************************************************************/
uint16_t USART_RxExt(USART_TypeDef *usart)
{
while (!(usart->STATUS & USART_STATUS_RXDATAV))
;
return (uint16_t)(usart->RXDATAX);
}
/***************************************************************************//**
* @brief
* Transmit one 4-9 bit frame.
*
* @details
* Depending on frame length configuration, 4-8 (least significant) bits from
* @p data are transmitted. If frame length is 9, 8 bits are transmitted from
* @p data and one bit as specified by CTRL register, BIT8DV field. Please
* refer to USART_TxExt() for transmitting 9 bit frame with full control of
* all 9 bits.
*
* Notice that possible parity/stop bits in asynchronous mode are not
* considered part of specified frame bit length.
*
* @note
* This function will stall if buffer is full, until buffer becomes available.
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @param[in] data
* Data to transmit. See details above for further info.
******************************************************************************/
void USART_Tx(USART_TypeDef *usart, uint8_t data)
{
/* Check that transmit buffer is empty */
while (!(usart->STATUS & USART_STATUS_TXBL));
usart->TXDATA = (uint32_t)data;
}
/***************************************************************************//**
* @brief
* Transmit two 4-9 bit frames, or one 10-16 bit frame.
*
* @details
* Depending on frame length configuration, 4-8 (least significant) bits from
* each byte in @p data are transmitted. If frame length is 9, 8 bits are
* transmitted from each byte in @p data adding one bit as specified by CTRL
* register, BIT8DV field, to each byte. Please refer to USART_TxDoubleExt()
* for transmitting two 9 bit frames with full control of all 9 bits.
*
* If frame length is 10-16, 10-16 (least significant) bits from @p data
* are transmitted.
*
* Notice that possible parity/stop bits in asynchronous mode are not
* considered part of specified frame bit length.
*
* @note
* This function will stall if buffer is full, until buffer becomes available.
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @param[in] data
* Data to transmit, the least significant byte holds the frame transmitted
* first. See details above for further info.
******************************************************************************/
void USART_TxDouble(USART_TypeDef *usart, uint16_t data)
{
/* Check that transmit buffer is empty */
while (!(usart->STATUS & USART_STATUS_TXBL))
;
usart->TXDOUBLE = (uint32_t)data;
}
/***************************************************************************//**
* @brief
* Transmit two 4-9 bit frames, or one 10-16 bit frame with extended control.
*
* @details
* Notice that possible parity/stop bits in asynchronous mode are not
* considered part of specified frame bit length.
*
* @note
* This function will stall if buffer is full, until buffer becomes available.
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @param[in] data
* Data to transmit with extended control. Contains two 16 bit words
* concatenated. Least significant word holds frame transitted first. If frame
* length is 4-9, two frames with 4-9 least significant bits from each 16 bit
* word are transmitted.
* @par
* If frame length is 10-16 bits, 8 data bits are taken from the least
* significant 16 bit word, and the remaining bits from the other 16 bit word.
* @par
* Additional control bits are available as documented in the EFM32 reference
* manual (set to 0 if not used). For 10-16 bit frame length, these control
* bits are taken from the most significant 16 bit word.
******************************************************************************/
void USART_TxDoubleExt(USART_TypeDef *usart, uint32_t data)
{
/* Check that transmit buffer is empty */
while (!(usart->STATUS & USART_STATUS_TXBL))
;
usart->TXDOUBLEX = data;
}
/***************************************************************************//**
* @brief
* Transmit one 4-9 bit frame with extended control.
*
* @details
* Notice that possible parity/stop bits in asynchronous mode are not
* considered part of specified frame bit length.
*
* @note
* This function will stall if buffer is full, until buffer becomes available.
*
* @param[in] usart
* Pointer to USART/UART peripheral register block.
*
* @param[in] data
* Data to transmit with extended control. Least significant bits contains
* frame bits, and additional control bits are available as documented in
* the EFM32 reference manual (set to 0 if not used).
******************************************************************************/
void USART_TxExt(USART_TypeDef *usart, uint16_t data)
{
/* Check that transmit buffer is empty */
while (!(usart->STATUS & USART_STATUS_TXBL))
;
usart->TXDATAX = (uint32_t)data;
}
/** @} (end addtogroup USART) */
/** @} (end addtogroup EM_Library) */
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