Here is an application note from Microchip describing how to implement a hardware Manchester decoder using the CLC and NCO peripherals found on some of their PIC microcontrollers.
The objective of this document is to demonstrate how the NCO and CLC peripherals found on PIC16F devices can be used as a Manchester Decoder. Traditional algorithms can be firmware intensive and leave very small amount of CPU cycles to service other application needs. The following approach involves using blocks that operate independently of the CPU clock and have zero CPU utilization, allowing designers to service their applications along with data encoding and decoding.
Interesting technique. Coincidently, I have been working on a MRF49XA design with a PIC16F1509 on it. Unfortunately, it seems you have to route the output of the CLC blocks manually to the MSSP part, which I have already reserved to I2C for some sensors.. So it uses quite a lot of I/O pins.
Oh well, the PIC16F1509 costs ~1 euro, so that’s cheap enough to use it separately for a manchester encoder/decoder only.,