ATA5743 ATMEL Corporation, ATA5743 Datasheet - Page 22

• Manufacturer Part Number: ATA5743
• Description: Ata5743 Uhf Ask/fsk Receiver
• Manufacturer: ATMEL Corporation

6.5
6.5.1
22
Digital Noise Suppression
ATA5743
Automatic Noise Suppression
Figure 6-18. Timing Characteristic of the Data Clock (Rising Edge on Pin DATA)
Figure 6-19. Timing Characteristic of the Data Clock (Falling Edge on Pin DATA)
After a data transmission, digital noise appears on the data output (see
To prevent digital noise from keeping the connected microcontroller busy, it can be suppressed
in two different ways.
The automatic noise suppression is illustrated in
Noise_Disable
receiver changes to bit-check mode at the end of a valid data stream. The digital noise is sup-
pressed and the level at pin DATA is High in that case. The receiver changes back to receiving
mode, if the bit check was successful.
This way of suppressing the noise is recommended if the data stream is Manchester or Bi-phase
coded and is active after power on.
Figure 6-22 on page 23
Note that if the last period of the data stream is a high period (rising edge to falling edge), a
pulse occurs on pin DATA. The length of the pulse depends on the selected baud-rate range.
Serial bi-directional
data line
Data_In
DATA_CLK
Data_Out
Serial bi-directional
data line
Data_In
DATA_CLK
(Table 6-9 on page
Data_Out
illustrates the behavior of the data output at the end of a data stream.
V
V
Ih
II
= 0.35
= 0.65
V
26) in the OPMODE register is set to “1” (default), the
V
V
X
S
S
t
Delay1
t
Delay
t
Delay1
t
Delay
t
Delay2
t
P_Data_Clk
t
Delay2
t
P_Data_Clk
V
V
Figure 6-21 on page
V
X
Ih
II
= 0.35
= 0.65
V
V
S
S
Figure 6-20 on page
23. If the bit
4839B–RKE–08/05
23).