yefj
Advanced Member level 5
Hello, i have the following example code of interrupt handling for efr32fg14 with its reference manual and data sheet shown bellow.
I cant in this code the mechanism which says,"whenever interrupt rises call this "USART0_RX_IRQHandler" function.
The closest thing i found is NVIC_EnableIRQ(USART0_RX_IRQn); but its not calling USART0_RX_IRQHandler.
How does the controller knows to call specifically USART0_RX_IRQHandler when interrupt flag rises?
Thanks.
I cant in this code the mechanism which says,"whenever interrupt rises call this "USART0_RX_IRQHandler" function.
The closest thing i found is NVIC_EnableIRQ(USART0_RX_IRQn); but its not calling USART0_RX_IRQHandler.
How does the controller knows to call specifically USART0_RX_IRQHandler when interrupt flag rises?
Thanks.
Code:
/***************************************************************************//**
* @file main_xg1_xg12_xg13_xg14.c
* @brief This project reads input on the UART RX port and echoes it back to the
* TX port one line at a time. It does not use the VCOM or stdio. See readme.txt
* for details.
*******************************************************************************
* # License
* <b>Copyright 2020 Silicon Laboratories Inc. www.silabs.com</b>
*******************************************************************************
*
* SPDX-License-Identifier: Zlib
*
* The licensor of this software is Silicon Laboratories Inc.
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* 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. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 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.
*
*******************************************************************************
* # Evaluation Quality
* This code has been minimally tested to ensure that it builds and is suitable
* as a demonstration for evaluation purposes only. This code will be maintained
* at the sole discretion of Silicon Labs.
******************************************************************************/
#include "em_device.h"
#include "em_chip.h"
#include "em_emu.h"
#include "em_cmu.h"
#include "em_gpio.h"
#include "em_usart.h"
#include "bsp.h"
// Size of the buffer for received data
#define BUFLEN 80
// Receive data buffer
uint8_t buffer[BUFLEN];
// Current position ins buffer
uint32_t inpos = 0;
uint32_t outpos = 0;
// True while receiving data (waiting for CR or BUFLEN characters)
bool receive = true;
/**************************************************************************//**
* @brief
* GPIO initialization
*****************************************************************************/
void initGpio(void)
{
CMU_ClockEnable(cmuClock_GPIO, true);
// Configure VCOM transmit pin to board controller as an output
GPIO_PinModeSet(BSP_BCC_TXPORT, BSP_BCC_TXPIN, gpioModePushPull, 1);
// Configure VCOM reeive pin from board controller as an input
GPIO_PinModeSet(BSP_BCC_RXPORT, BSP_BCC_RXPIN, gpioModeInput, 0);
// Enable VCOM connection to board controller
GPIO_PinModeSet(BSP_BCC_ENABLE_PORT, BSP_BCC_ENABLE_PIN, gpioModePushPull, 1);
}
/**************************************************************************//**
* @brief
* USART0 initialization (VCOM on xG1/xG12/xG13 boards)
*****************************************************************************/
void initUsart0(void)
{
CMU_ClockEnable(cmuClock_USART0, true);
// Default asynchronous initializer (115.2 Kbps, 8N1, no flow control)
USART_InitAsync_TypeDef init = USART_INITASYNC_DEFAULT;
// Configure and enable USART0
USART_InitAsync(USART0, &init);
// Enable NVIC USART sources
NVIC_ClearPendingIRQ(USART0_RX_IRQn);
NVIC_EnableIRQ(USART0_RX_IRQn);
NVIC_ClearPendingIRQ(USART0_TX_IRQn);
NVIC_EnableIRQ(USART0_TX_IRQn);
// Enable RX and TX for USART0 VCOM connection
USART0->ROUTELOC0 = BSP_BCC_RX_LOCATION | BSP_BCC_TX_LOCATION;
USART0->ROUTEPEN |= USART_ROUTEPEN_RXPEN | USART_ROUTEPEN_TXPEN;
}
/**************************************************************************//**
* @brief
* The USART0 receive interrupt saves incoming characters.
*****************************************************************************/
void USART0_RX_IRQHandler(void)
{
// Get the character just received
buffer[inpos] = USART0->RXDATA;
// Exit loop on new line or buffer full
if ((buffer[inpos] != '\r') && (inpos < BUFLEN))
inpos++;
else
receive = false; // Stop receiving on CR
// Clear the requesting interrupt before exiting the handler
USART_IntClear(USART0, USART_IF_RXDATAV);
}
/**************************************************************************//**
* @brief
* The USART0 transmit interrupt outputs characters.
*****************************************************************************/
void USART0_TX_IRQHandler(void)
{
// Send a previously received character
if (outpos < inpos)
USART0->TXDATA = buffer[outpos++];
else
/*
* Need to disable the transmit buffer level interrupt in this IRQ
* handler when done or it will immediately trigger again upon exit
* even though there is no data left to send.
*/
{
receive = true; // Go back into receive when all is sent
USART_IntDisable(USART0, USART_IEN_TXBL);
}
// Clear the requesting interrupt before exiting the handler
USART_IntClear(USART0, USART_IF_TXBL);
}
/**************************************************************************//**
* @brief
* Main function
*****************************************************************************/
int main(void)
{
uint32_t i;
// Chip errata
CHIP_Init();
// Initialize GPIO and USART0
initGpio();
initUsart0();
while (1)
{
// Zero out buffer
for (i = 0; i < BUFLEN; i++)
buffer[i] = 0;
// Enable receive data valid interrupt
USART_IntEnable(USART0, USART_IEN_RXDATAV);
// Wait in EM1 while receiving to reduce current draw
while (receive)
EMU_EnterEM1();
// Disable receive data valid interrupt
USART_IntDisable(USART0, USART_IEN_RXDATAV);
// Enable transmit buffer level interrupt
USART_IntEnable(USART0, USART_IEN_TXBL);
// Wait in EM1 while transmitting to reduce current draw
while (!receive)
EMU_EnterEM1();
// Reset buffer indices
inpos = outpos = 0;
}
}
