Yes you can use a UART with manchester encoding. For the transmit process you need access to a the 1X clock. You need to then XOR the NRZ data with the clock before applying the manchester encoded data to the transmission medium. Note that if only the 16X clock is available you can usually divide it to 1X with a 4-bit counter and then use a flipflop to derive a delayed version of the data that then comes in sync with this 1X clock. (The XORing process needs to have the clock synchronous with the data).

For receiving it is necessary to recover a clock out of the received bit stream. This clock will by nature end up being a 1X clock. You can then operate the receiving side of the UART at a 1X clock, or even better is to use a small PLL chip to up-convert the recovered clock to a 16x rate and let the UART sample the decoded manchester data at a 16X rate.

I hope this helps. It can be hard to implement this with an embedded microcontroller UART because many times the manchester circuits you provide cannot easily acess the baud rate clocks that the UART operates from.

There used to also be a couple of chips from the likes of Fairchld amd National that implemented a manchester interface including the parallel to serial and serial to parallel conversionions. These chips generally were more sophisticated than the UART approach in that they supported preambles for line balancing and PLL settling and incorporated framing via an illegal bit cell concept. These days most implementations of this type are done via IP placed into an FPGA.

Michael Karas