-42 dBm. If RSS_G is 1, the RSSI covers the received signal strength range of -55 to -2 dBm. The RSSID value
is also compared to the RSSI_thr threshold value of register 0x03.
If the digital value is greater than the threshold value, the RSSID pin is asserted according to the configuration of
the LVLDRSSI bit of register 0x17. If the LVLDRSSI bit is set to 1, the RSSID pin is asserted high, otherwise the
pin is asserted low. The output state of the RSSID pin is disabled while MODE is asserted. The RSSI function is
only available in continuous mode, as discussed below.
4 Operating Modes
The TRC104 can operate in one of five modes: Sleep, Stop, Stand-by, Configuration or Active TX/RX. Figure 8
details the state transitions between the operating modes.
T
R
C
1
0
4
O
p
e
r
a
t
i
n
g
M
o
d
e
S
t
a
t
e
D
i
a
g
r
a
m
T
X
/
R
X
S
l
e
e
p
S
t
a
n
d
b
y
S
t
o
p
C
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f
i
g
Figure 8
There are three input pins that determine the operating mode for the TRC104. The states of these pins are shown
in Table 9 and associated timing diagrams are provided in the Sections below where needed.
Pin State
Operating Mode
PMODE CS MODE
Sleep Mode
0
0
1
1
1
1
X
0
0
1
0
0
1
Stop Mode
0
Standby Mode
0
Configuration Mode
Transmit Load/Receive Mode
Burst Transmit
0
1
1 → 0
X – Don’t Care
Table 9
4.1 Sleep Mode
Sleep Mode provides the lowest TRC104 current consumption, typically less than 0.4 µA. No serial transactions
can occur while in Sleep Mode. The contents of the FIFO and the internal configuration registers are not
maintained in Sleep Mode. When waking from Sleep Mode the TRC104 executes a power-up reset, which takes
120 ms. Any operation to the TRC104 must wait until the reset period is complete. Following a sleep cycle,
configuration registers must be rewritten to utilize operating parameters other than the power on default settings.
Figure 9 demonstrates the states of the mode control pins and the timing related to Sleep Mode. For minimum
current consumption, hold the SDAT, SCLK, INT and RSSID pins low in this mode. 100K pull-down resistors can
be used for this purpose.
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TRC104 - 08/13/09
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