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##

# 2.110.19 SERCOMx_USART_WriteFreeBufferCountGet Function

## C

    /* x = SERCOM instance number */

    /* Ring buffer mode */

    size_t SERCOMx_USART_WriteFreeBufferCountGet(void)

## Summary

Returns the number of bytes of free space available in the internal transmit buffer

## Description

This function returns the number of bytes of free space available in the internal transmit buffer

## Precondition

SERCOMx_USART_Initialize must have been called for the associated SERCOM_USART instance.

## Parameters

None

## Returns

The API returns the number of bytes of free space in the transmit buffer. If 9-bit mode is enabled, then the return value indicates the number of 9-bit data that can be copied into the ring buffer.

## Example

    uint8_t txBuffer[10];

    // Check if there is space for writing at-least 10 characters to the transmit buffer
    if (SERCOM0_USART_WriteFreeBufferCountGet() >= 10)
    {
        SERCOM0_USART_Write((uint8_t*)txBuffer, 10);
    }

## Remarks

None