Rainbow Electronics T5761 - Manual (Page 26)

26
T5760/T5761
4561B–RKE–10/02
Bit 15 is followed by the equivalent time window t9. During this window, the equivalence
acknowledge pulse t8 (E_Ack) occurs if the just programmed mode word is equivalent to
the mode word that was already stored in that register. E_Ack should be used to verify
that the mode word was correctly transferred to the register. The register must be pro-
grammed twice in that case.
Programming of a register is possible both in sleep-mode and in active-mode of the
receiver.
During programming, the LNA, LO, lowpass filter IF-amplifier and the FSK/ASK
Manchester demodulator are disabled.
The programming start pulse t1 initiates the programming of the configuration registers.
If bit 1 is set to ’1’, it represents the OFF command to set the receiver back to polling
mode at the same time. For the length of the programming start pulse t1, the following
convention should be considered:
• t1(min) < t1 < 5632 T
Clk
:
t1(min) is the minimum specified value for the relevant BR_Range
Programming respectively OFF command is initiated if the receiver is not in reset mode.
If the receiver is in reset mode, programming respectively Off command is not initiated
and the reset marker RM is still present at Pin DATA.
This period is generally used to switch the receiver to polling mode or to start the
programming of a register. In reset condition, RM is not cancelled by accident.
• t1 > 7936 x T
Clk
Programming respectively OFF command is initiated in any case. The registers
OPMODE and LIMIT are set to the default values. RM is cancelled if present.
This period is used if the connected microcontroller detected RM. If the receiver oper-
ates in default mode, this time period for t1 can generally be used.
Note that the capacitive load at Pin DATA is limited.
Data Interface
The data interface (see Figure 32) is designed for automotive requirements. It can be
connected via the pull-up resistor R
pup
up to 20 V and is short-circuit-protected.
The applicable pull-up resistor R
pup
depends on the load capacity C
L
at Pin DATA and
the selected BR_range (see Table 12).
Table 12. Applicable R
pup
- BR_range Applicable R
pup
C
L
£ 1nF
B0 1.6 k W to 47 k W
B1 1.6 k W to 22 k W
B2 1.6 k W to 12 k W
B3 1.6 k W to 5.6 k W
C
L
£
100pF
B0 1.6 k
W
to 470 k
W
B1 1.6 k
W
to 220 k
W
B2 1.6 k
W
to 120 k
W
B3 1.6 k
W
to 56 k
W