ATA5823 ATMEL Corporation, ATA5823 Datasheet - Page 58

• Manufacturer Part Number: ATA5823
• Description: Uhf Ask/fsk Transceiver Ata5823 Ata5824
• Manufacturer: ATMEL Corporation

14.1.7
Figure 14-7. Receiving Mode (TMODE = 1)
58
ATA5823/ATA5824
Receiving Mode
SDO_TMDO
Demod_Out
Bit-check mode
0
If the Bit-check was successful for all bits specified by N
receiving mode. To activate a connected microcontroller, bit CLK_ON in control register 3 is 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 inactive (no data
transfer via the serial interface), the RX data stream is available on pin SDO_TMDO
14-7).
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 permanently 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, like 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 14-8 on page
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 round up.
If the TX/RX data buffer control logic detects the start bit, the data stream is written in the TX/RX
data buffer byte by byte. The start bit is part of the first data byte and must be different from the
bits of the preburst. If the preburst consists of a sequence of “00000...”, the start bit must be a 1.
If the preburst consists of a sequence of “11111...”, the start bit must be a 0.
Lim_min_2T
Lim_max_2T
T
Bit-check ok
Lim_max_2T
0
0
0
Preburst
0
=
=
0
=
(Lim_max_2T 1
0
Lim_min
Lim_min
0
0
Start-
59. Only two distances between two edges in Manchester and Bi-phase
bit
1
+
+
0
Figure 14-8 on page
Lim_max
Lim_max
–
1
0
Byte 1
0
T
XDCLK
–
0
+
Lim_max Lim_min
Lim_max Lim_min
0
Receiving mode
0
1
1
–
–
59). The TX/RX data buffer is only usable for
1
1
Byte 2
0
0
1
2
2
Bit-check
T
1
Lim_min_2T
0
Figure 13-1 on page
1
, the transceiver switches to
0
1
=
Byte 3
Lim_min_2T
1
0
0
4829D–RKE–06/06
47).
T
(Figure
XDCLK