1.2.21.5 1.3.25.5 1.4.21.5 1.5.25.5 1.6.22.5 1.7.23.5 1.9.19.5 1.29.23.5 1.30.18.5 1.31.18.5 1.32.26.5 1.33.16.5 1.37.18.5 1.38.21.5 1.39.18.5 1.40.20.5 SERCOMx_USART_WriteCountGet Function
C
/* x = SERCOM instance number */
/* Non-blocking and ring buffer mode */
size_t SERCOMx_USART_WriteCountGet( void )
Summary
Non-blocking mode
Gets the byte count of processed bytes for a given USART write operation
Ring buffer mode
Returns the number of bytes pending to be transmitted out in the transmit buffer.
Description
Non-blocking mode
This function gets the count of processed bytes for an on-going or last completed USART Transmit operation. This function can be used to track the progress of the non-blocking transmit operation.
Ring buffer mode
This function returns the number of bytes of data pending for transmission.
Precondition
SERCOMx_USART_Initialize must have been called for the associated USART instance.
Parameters
None.
Returns
Non-blocking mode
Returns count of bytes currently completed/processed from the current Transmit buffer for interrupt non-blocking mode. In 9-bit mode, it returns the number of 9-bit data processed.
Ring buffer mode
The API returns the number of bytes that are pending for transmission in the internal transmit buffer. If 9-bit mode is enabled, then the return value indicates the number of 9-bit data pending transmission.
Example
Non-blocking mode
size_t count; count = SERCOM0_USART_WriteCountGet(); if(count < COUNT_EXPECTED) { //More bytes are expected to transmit, wait }
Ring buffer mode
if (SERCOM0_USART_WriteCountGet() == 0)
{
// All the data has been transmitted out.
}
Remarks
None