Lpc2000

Hi,

I am migrating a serial communications interface (Modbus) to a LPC2138 
processor. The Modbus spec defines that an end of message has occurred 
when a period equal to 3.5 characters has passed since the last 
character has been received.

The LPC uart can generate an interrupt if the receive buffer has 
characters in it and no character has been received for a period of 3.5 
- 4.5 characters.

I would like to use this feature for detecting the end of a received 
message. The problem I have is that if I service an interrupt due the 
the buffer being filled, and it also happens that that last character in 
the buffer was the last character for the received message, the receive 
time-out interrupt will not occur, resulting in the end of message not 
being detected.

Is there a solution, other than using a buffer length of 1 and using a 
timer to measure the inter message gap?

Cheers,

Peter.

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