at91cap7e ATMEL Corporation, at91cap7e Datasheet - Page 360

• Manufacturer Part Number: at91cap7e
• Description: Customizable Microcontroller
• Manufacturer: ATMEL Corporation

Figure 29-18. ASK Modulator Output
Figure 29-19. FSK Modulator Output
29.6.3.6
Figure 29-20. Synchronous Mode Character Reception
360
Uptstream Frequency F0
Uptstream Frequencies
FSK Modulator
unipolar output
ASK Modulator
default polarity
unipolar output
[F0, F0+offset]
default polarity
AT91CAP7E
NRZ stream
NRZ stream
Manchester
Manchester
encoded
Synchronous Receiver
encoded
Output
Output
data
data
Example: 8-bit, Parity Enabled 1 Stop
Baud Rate
Sampling
Clock
RXD
Txd
Txd
1
1
switches to receiving mode. The demodulated stream is sent to the Manchester decoder.
Because of bit checking inside RF IC, the data transferred to the microcontroller is reduced by a
user-defined number of bits. The Manchester preamble length is to be defined in accordance
with the RF IC configuration.
In synchronous mode (SYNC = 1), the receiver samples the RXD signal on each rising edge of
the Baud Rate Clock. If a low level is detected, it is considered as a start. All data bits, the parity
bit and the stop bits are sampled and the receiver waits for the next start bit. Synchronous mode
operations provide a high speed transfer capability.
Configuration fields and bits are the same as in asynchronous mode.
Figure 29-20
Start
illustrates a character reception in synchronous mode.
D0
D1
0
0
D2
D3
D4
0
0
D5
D6
D7
Parity Bit
Stop Bit
1
1
8549A–CAP–10/08