turning off interrupt after one buffer itteration

[yefj]

Hello, This code works in endless loop.I want to send the buffer only once

how to i turn off this trigger after one itteration?
Thanks.

#include "em_device.h"
#include "em_chip.h"
#include "em_cmu.h"
#include "em_gpio.h"
#include "em_usart.h"
#include "em_ldma.h"

#define TX_BUFFER_SIZE   10
#define RX_BUFFER_SIZE   TX_BUFFER_SIZE

uint8_t TxBuffer[TX_BUFFER_SIZE] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09};
uint32_t TxBufferIndex = 0;

uint8_t RxBuffer[RX_BUFFER_SIZE] = {0};
uint32_t RxBufferIndex = 0;

/**************************************************************************//**
 * @brief USART1 TX IRQ Handler
 *****************************************************************************/
void USART1_TX_IRQHandler(void)
{
  // Send and receive incoming data
  USART_Tx(USART1, TxBuffer[TxBufferIndex++]);

  // Stop sending once we've gone through the whole TxBuffer
  if (TxBufferIndex == TX_BUFFER_SIZE)
  {
    TxBufferIndex = 0;
  }
}

/**************************************************************************//**
 * @brief USART1 RX IRQ Handler
 *****************************************************************************/
void USART1_RX_IRQHandler(void)
{
  // Send and receive incoming data
  RxBuffer[RxBufferIndex++] = USART_Rx(USART1);

  // Stop once we've filled up our buffer
  if (RxBufferIndex == RX_BUFFER_SIZE)
  {
    // Place breakpoint here and observe RxBuffer
    // RxBuffer should contain 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9
    RxBufferIndex = 0;
  }
}

/**************************************************************************//**
 * @brief Initialize USART1
 *****************************************************************************/
void initUSART1 (void)
{
    CMU_ClockEnable(cmuClock_GPIO, true);
    CMU_ClockEnable(cmuClock_USART1, true);

    // Configure GPIO mode
    GPIO_PinModeSet(gpioPortC, 8, gpioModePushPull, 0); // US1_CLK is push pull
    GPIO_PinModeSet(gpioPortC, 9, gpioModePushPull, 1); // US1_CS is push pull
    GPIO_PinModeSet(gpioPortC, 6, gpioModePushPull, 1); // US1_TX (MOSI) is push pull
    GPIO_PinModeSet(gpioPortC, 7, gpioModeInput, 1);    // US1_RX (MISO) is input

    // Start with default config, then modify as necessary
    USART_InitSync_TypeDef config = USART_INITSYNC_DEFAULT;
    config.master       = true;            // master mode
    config.baudrate     = 1000000;         // CLK freq is 1 MHz
    config.autoCsEnable = true;            // CS pin controlled by hardware, not firmware
    config.clockMode    = usartClockMode0; // clock idle low, sample on rising/first edge
    config.msbf         = true;            // send MSB first
    config.enable       = usartDisable;    // Make sure to keep USART disabled until it's all set up
    USART_InitSync(USART1, &config);

    // Set USART pin locations
    USART1->ROUTELOC0 = (USART_ROUTELOC0_CLKLOC_LOC11) | // US1_CLK       on location 11 = PC8 per datasheet section 6.4 = EXP Header pin 8
                        (USART_ROUTELOC0_CSLOC_LOC11)  | // US1_CS        on location 11 = PC9 per datasheet section 6.4 = EXP Header pin 10
                        (USART_ROUTELOC0_TXLOC_LOC11)  | // US1_TX (MOSI) on location 11 = PC6 per datasheet section 6.4 = EXP Header pin 4
                        (USART_ROUTELOC0_RXLOC_LOC11);   // US1_RX (MISO) on location 11 = PC7 per datasheet section 6.4 = EXP Header pin 6

    // Enable USART pins
    USART1->ROUTEPEN = USART_ROUTEPEN_CLKPEN | USART_ROUTEPEN_CSPEN | USART_ROUTEPEN_TXPEN | USART_ROUTEPEN_RXPEN;

    // Enabling TX interrupts to transfer whenever
    // there is room in the transmit buffer
    USART_IntClear(USART1, USART_IF_TXBL);
    USART_IntEnable(USART1, USART_IEN_TXBL);
    NVIC_ClearPendingIRQ(USART1_TX_IRQn);
    NVIC_EnableIRQ(USART1_TX_IRQn);

    // Enabling RX interrupts to trigger whenever
    // a new packet arrives from the slave
    USART_IntClear(USART1, USART_IF_RXDATAV);
    USART_IntEnable(USART1, USART_IEN_RXDATAV);
    NVIC_ClearPendingIRQ(USART1_RX_IRQn);
    NVIC_EnableIRQ(USART1_RX_IRQn);

    // Enable USART1
    USART_Enable(USART1, usartEnable);
}

/**************************************************************************//**
 * @brief Main function
 *****************************************************************************/
int main(void)
{
  // Initialize chip
  CHIP_Init();

  // Initialize USART1 as SPI master
  initUSART1();

  // After the USART is initialized transfers will automatically start based off of certain interrupt flag conditions
  // A new packet will be sent to the slave whenever the TX Buffer is empty after a previous successful transfer
  // and a packet will be sent from the slave back whenever it receives a packet from the master and will be handled
  // by the USART_RX_IRQHandler
  while(1);
}

 

[danadakk]

What processor are you using ?

Regards, Dana.

 

[yefj]

Hello Danadakk,i am using EFM32.
We send the data from the trigger handle function.
What causes to call the first time our trigger hanle function?
Thanks.

 

[yefj]

Hello i want to gain the intuition regarding the TXBL,The manual says.
"When data has been moved from the TX buffer, the TXBL bit in the USARTn_STATUS register is set, indicating that a new transmit byte may be written "
We need to call our handle function in order to transmit which will causeTXBL trigger.
What causes the trigger to go high before we even sent some thing?

 

[danadakk]

In addition to the interrupt flag TXC in USARTn_IF and status flag TXC in USARTn_STATUS which are
set when the transmitter is idle, TXBL in USARTn_STATUS and the TXBL interrupt flag in USARTn_IF
are used to indicate the level of the transmit buffer. TXBIL in USARTn_CTRL controls the level at which
these bits are set. If TXBIL is cleared, they are set whenever the transmit buffer becomes empty, and if
TXBIL is set, they are set whenever the transmit buffer goes from full to half-full or empty. Both the TXBL
status flag and the TXBL interrupt flag are cleared automatically when their condition becomes false

Does that answer your question ?

Regards, Dana.