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Function RTSendBufferCount

The status of the send buffer can be enquired with this function:

int RTSendBufferCount(int Port);

Parameters

Port

Must have value RT_COM1 .. RT_COM4.

return value

The number of bytes currently in the send buffer for the corresponding port.

Please note that the last byte may still be in the send shift register even if this function returns 0. To be sure all data has been transmitted, check bit RT_TX_SHIFT_EMPTY in the Line Status register.

Example:

while (RTSendBufferCount(P) > 0) 
{ 
   printf("waiting for the send buffer... "); 
   RTWait(); 
} 

while (!(RTLineStatus(P) & RT_TX_SHIFT_EMPTY)) 
   printf("waiting for the UART... ");

Serial Port I/O

Function RTSendBlockTimed

Function RTReceiveBufferCount