u3742bm ATMEL Corporation, u3742bm Datasheet - Page 22

• Manufacturer Part Number: u3742bm
• Description: Uhf Ask/fsk Receiver
• Manufacturer: ATMEL Corporation

Table 10. Effect of the Configuration Word Lim_max
Conservation of the Register
Information
Figure 23. Generation of the Power-on Reset
22
0
0
0
0
1
1
1
.
.
.
.
.
.
U3742BM
POR
DATA (U3742BM)
V
S
Lim_max < 12 is not applicable
0
0
0
1
1
1
1
.
.
.
.
.
.
1
1
1
1
1
1
1
.
.
.
.
.
.
Lim_max
X
1
1
1
0
1
1
1
.
.
.
.
.
.
The U3742BM has an integrated power-on reset (POR) and brown-out detection cir-
cuitry to provide a mechanism to preserve the RAM register information.
According to Figure 23, a power-on reset is generated if the supply voltage V
below the threshold voltage V
configuration registers in that condition. Once V
after the minimum reset period t
the receiver is turned on.
To indicate that condition, the receiver displays a reset marker (RM) at pin DATA after a
reset. The RM is represented by the fixed frequency f
canceled via an 'L' pulse t
•
•
By means of that mechanism, the receiver cannot lose its register information without
communicating that condition via the reset marker RM.
t
f
cannot be misinterpreted by the connected microcontroller.
If the receiver is set back to polling mode via pin DATA, RM cannot be cancelled by
accident if t
Configuration Register” on page 23.
Rst
RM
0
0
1
0
0
1
1
.
.
.
.
.
.
is lower than the lowest feasible frequency of a data signal. This means, RM
1
is applied according to the proposal in the section “Programming the
0
1
0
0
1
0
1
.
.
.
.
.
.
V
ThReset
1
at pin DATA. The RM implies the following characteristics:
ThReset
(USA: T
Rst
. A POR is also generated when the supply voltage of
. The default parameters are programmed into the
(T
Lim_max
Lim_max
Upper Limit Value for Bit Check
= (Lim_max - 1) × XLim × T
= 375 µs, Europe: T
S
1/f
exceeds V
24 (Default)
RM
RM
12
13
14
61
62
63
at a 50% duty cycle. RM can be
ThReset
Lim_max
, the POR is canceled
= 381 µs)
Clk
)
4735A–RKE–11/03
S
drops