AT90PWM2B-16SU View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT90PWM2B-16SU

8-bit Atmel Microcontroller with 8K Bytes In-System Programmable Flash

Atmel Corporation 

AT90PWM2/3/2B/3B

19.3.3

Manchester encoding

Manchester encoding (also know as Biphase Code) is a synchronous clock encoding technique

used to encode the clock and data of a synchronous bit stream. In this technique, the actual

binary data to be transmitted are not sent as a sequence of logic 1's and 0's as in level encoded

way as in standard USART (known technically as Non Return to Zero (NRZ)). Instead, the bits

are translated into a slightly different format that has a number of advantages over using straight

binary encoding (i.e. NRZ).

Manchester encoding follows the rules:

• If the original data is a Logic 1, the Manchester code is: 0 to 1 (upward transition at bit

center)

• If the original data is a Logic 0, the Manchester code is: 1 to 0 (downward transition at bit

center)

Figure 19-2. Manchester Bi-phase levels

19.3.3.1

Logical 0

Logical 1

Manchester frame

The USART supports Manchester encoded frames with the following characteristics:

• One start bit Manchester encoded (logical ‘1’)

• 5, 6, 7, 8, 9, 13, 14,15,16,17 data bits in transmission or reception (MSB or LSB first)

• The number of data bit in a frame is independently configurable in reception and

transmission mode.

• One or Two stop bits (level encoded)

Figure 19-3. Manchester Frame example

Encoder Clock

Manchester Data

Binary Data

10011110100101010

Start

Data Bits

Stop

Bit

(up to 17 data bit)

Bits

4317K–AVR–03/2013

214

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