ATA5423 ATMEL Corporation, ATA5423 Datasheet - Page 59

• Manufacturer Part Number: ATA5423
• Manufacturer: ATMEL Corporation

9.1.7
Figure 9-8.
4841A–RKE–02/05
Receiving Mode
SDO_TMDO
Demod_Out
Receiving Mode (TMODE = 1)
Bit
check ok
Bit-check mode
0
In the presence of a valid transmitter signal, T
nal, f
longer period for T
If the bit check was successful for all bits specified by N
receiving mode. To activate a connected microcontroller, the bits VSOUT_EN and CLK_ON in
control register 3 are set to “1”. An interrupt is issued at pin IRQ if the control bits T_MODE = 0
and P_MODE = 0.
If the transparent mode is active (T_MODE = 1) and the level on pin CS is low (no data transfer
via the serial interface), the RX data stream is available on pin SDO_TMDO
If the transparent mode is inactive (T_MODE = 0), the received data stream is buffered in the
TX/RX data buffer (see
Manchester and Bi–phase coded signals. It is always possible to transfer the data from the data
buffer via the 4–wire serial interface to a microcontroller (see
Buffering of the data stream:
After a successful bit check, the transceiver switches from bit-check mode to receiving mode. In
receiving mode the TX/RX data buffer control logic is active and examines the incoming data
stream. This is done, as in the bit check, by subsequent time frame checks where the distance
between two edges is continuously compared to a programmable time window as illustrated in
Figure 9-9 on page
phase coded signals are valid (T and 2T).
The limits for T are the same as used for the bit check. They can be programmed in control
register 5 and 6 (Lim_min, Lim_max).
The limits for 2T are calculated as follows:
Lower limit of 2T:
Upper limit of 2T:
If the result of Lim_min_2T or Lim_max_2T is not an integer value, it will be rounded up.
Lim_min_2T
T
Lim_max_2T
T
Lim_min_2T
Lim_max_2T
0
0
Signal
Preburst
0
, and the count of the bits, N
0
=
=
0
=
=
Lim_min_2T
0
Lim_max_2T - 1
Lim_min
Lim_min
0
Bit–check
0
60. Only two time differences between two edges in Manchester and Bi–
Start-
bit
1
+
+
0
Lim_max
, requiring a higher value for the transmitter pre–burst, T
Figure 9-9 on page
Lim_max
T
1
XDCLK
Byte 1
0
0
T
XDCLK
–
0
+
ATA5423/25/28/29 [Preliminary]
Lim_max Lim_min
0
Lim_max Lim_min
Bit–check
Receiving mode
0
1
. A higher value for N
1
–
Bit–check
–
60). The TX/RX data buffer is only usable for
1
Byte 2
1
0
is dependent on the frequency of that sig-
0
/2
/2
1
Bit–check
1
Figure 8-1 on page
0
1
, the transceiver switches to
Bit–check
0
Byte 3
1
1
therefore results in a
0
(Figure
0
49).
Preburst
9-8).
.
59