TFBS4711 echoes the TXD signal at the RXD output during transmission. For communication this signal is to be correctly ignored by the controller or the software.
Is this a problem for the 11U68 or 11E68 (or any other LPC for that matter) while the device is in ISP boot mode? The user manual documentation doesn't mention anything about it being a problem.
It's not a problem when the 11U68 is running as we can disable the RX interrupts when we are transmitting.
