FreeWave Technologies Inc. AMI0032AT Manuale Utente
Spread Spectrum Wireless Data Transceiver User Manual
Preliminary GXM Manual
Version 0.2
33
PRELIMINARY
The following table shows the changes at different Lowpower Mode settings. The actual current draw
depends on many factors. The table below gives only a qualitative indication of supply current savings. A
low number reduces latency and a high number reduces current consumption.
depends on many factors. The table below gives only a qualitative indication of supply current savings. A
low number reduces latency and a high number reduces current consumption.
Setting
Description
0 Lowpower,
disabled
1
LED’s dimmed, transceiver remains awake, transceiver is listening to the
Master’s transmissions on every slot, and transceiver’s data port is shut down
if the RTS line is deasserted (low). In this case, the transceiver needs to be
awakened before it will be able to send data to the Master.
Master’s transmissions on every slot, and transceiver’s data port is shut down
if the RTS line is deasserted (low). In this case, the transceiver needs to be
awakened before it will be able to send data to the Master.
2
LED’s dimmed, transceiver sleeps every other slot
3
LED’s dimmed, transceiver sleeps 2 of 3 slots
4-31
LED’s dimmed, transceiver sleeps the number of slots corresponding to the
setting. For example, with a setting of 31 the transceiver sleeps 30 of 31 slots.
setting. For example, with a setting of 31 the transceiver sleeps 30 of 31 slots.
I
MPORTANT
N
OTES
1.
Lowpower Mode is used only in MultiPoint Slaves using serial protocol. Power savings occur only
when the Slave is linked. No power savings occur when the Slave is transmitting data. Lowpower
Mode is of little value when a Slave has a constant, high throughput. MCUSpeed must be set to
‘0’ and RF Data Rate must be set to ‘3’ for Lowpower Mode to operate properly.
when the Slave is linked. No power savings occur when the Slave is transmitting data. Lowpower
Mode is of little value when a Slave has a constant, high throughput. MCUSpeed must be set to
‘0’ and RF Data Rate must be set to ‘3’ for Lowpower Mode to operate properly.
2.
Additional power savings may be realized when the Number Repeaters is set to 1.
3.
To communicate to an RS232 port of a transceiver that is in Lowpower Mode, the RTS line must
be held high to wake it up. The transceiver will wake up within approximately 20 milliseconds of
when RTS goes high.
be held high to wake it up. The transceiver will wake up within approximately 20 milliseconds of
when RTS goes high.
4.
If the RTS line on the Slave is held high, the transceiver will remain in normal operation
regardless of the Lowpower Mode setting. Once RTS is dropped the transceiver reverts to the
Lowpower Mode.
regardless of the Lowpower Mode setting. Once RTS is dropped the transceiver reverts to the
Lowpower Mode.
5.
If the transceiver has the DTRConnect option set to 1 or 2 and if the Lowpower Mode enabled
(set to 1-31), the RTS line on the transceiver must be asserted for the ‘DTRConnect’ feature to
operate properly.
(set to 1-31), the RTS line on the transceiver must be asserted for the ‘DTRConnect’ feature to
operate properly.
(A)
H
IGH
N
OISE
The High Noise Option is useful in determining if out of band interference is affecting a radio link. A
setting of 1 will provide a reduction of gain in the front end circuit thereby decreasing the affect of any out
of band noise. The results will be seen as a lower signal value and a much lower noise value (as found in
Radio Statistics or Diagnostics). If the noise is not reduced by a greater amount than the signal, the
interference is most likely an in band issue.
setting of 1 will provide a reduction of gain in the front end circuit thereby decreasing the affect of any out
of band noise. The results will be seen as a lower signal value and a much lower noise value (as found in
Radio Statistics or Diagnostics). If the noise is not reduced by a greater amount than the signal, the
interference is most likely an in band issue.
When a noise problem is shown to be helped by way of the High Noise option, chances are that the noise
may be further squelched by use of a bandpass filter available for sale from FreeWave Technologies.
may be further squelched by use of a bandpass filter available for sale from FreeWave Technologies.
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