Lpc2000

I am driving a 485 transceiver (SN65HVD10) with the LPC2104.  The 
RE/ and DE lines are tied together and to a GPIO pin for direction 
selection.  My problem is that when I enable transmission the bus is 
driven low and a pulse is seen at my RXD input causing an 
interrupt.  I have tried disabling the UART1 interrupt before I 
toggle the direction pins of the 485 transceiver but the receive 
interrupt fires off as soon as I enable the UART interrupts again.  
Tying the direction pins of the tranceiver results in a race 
condition so I have added a small delay to let the pins settle.

Thanks for the help

Richard