Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Data Sheet

Product codes
AT91SAM9M10-G45-EK
Page of 1361
 485
SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
 
Figure  31-16.
Manchester Error Flag
When the start frame delimiter is a sync pattern (ONEBIT field at 0), both command and data delimiter are sup-
ported. If a valid sync is detected, the received character is written as RXCHR field in the US_RHR register and the
RXSYNH is updated. RXCHR is set to 1 when the received character is a command, and it is set to 0 if the
received character is a data. This mechanism alleviates and simplifies the direct memory access as the character
contains its own sync field in the same register.
As the decoder is setup to be used in unipolar mode, the first bit of the frame has to be a zero-to-one transition.
31.7.3.6
Radio Interface: Manchester Encoded USART Application
This section describes low data rate RF transmission systems and their integration with a Manchester encoded
USART. These systems are based on transmitter and receiver ICs that support ASK and FSK modulation
schemes.
The goal is to perform full duplex radio transmission of characters using two different frequency carriers. See the
configuration in 
.
Manchester
encoded
data
Txd
SFD
Preamble Length 
is set to 4
Elementary character bit time
Manchester
Coding Error
detected
sampling points
Preamble subpacket
and Start Frame Delimiter
were successfully
decoded
Entering USART character area