User's Manual

Spread Spectrum Wireless Data Transceiver User Manual

LUM0002AF Rev E Version 6.3 39

(8) RETRY TIME OUT

The Retry Time Out parameter in a Slave or Repeater sets the delay the unit will wait before dropping the

connection to a Master or Repeater in MultiPoint mode. The factory default is set at the maximum of 255.

The maximum setting means that if 1 packet in 255 is sent successfully from the Master to the Slave or

Repeater, the link will be maintained. The minimum setting is 8. This allows a Slave or Repeater to drop a

connection if less than 1 in 8 consecutive packets is successfully received from the Master.

On the other hand, the function in the Master is effectively the same. With a setting of 255, the Master

will allow a Slave or Repeater to stay connected as long as 1 packet in 255 is successfully received at the

Master.

The Retry Time Out parameter is useful when a MultiPoint network has a roving Master or Slave(s). As

the link gets weaker, a lower setting will allow a poor link to break in search of a stronger one.

Note: Setting Retry Time Out to 20 is recommended in areas where several FreeWave networks exist.

This setting will allow Slaves and Repeaters to drop the connection if the link becomes too weak,

while at the same time prevent errant disconnects due to interference from neighboring networks.

While intended primarily for MultiPoint networks, the Retry Time Out parameter may also be modified in

Point-to-Point networks. However, the value in Point-to-Point mode should not be set to less than 151.

(9)

LOWPOWER MODE

The Lowpower Mode feature allows a MultiPoint Slave to consume less power. This is achieved primarily

by dimming the transceiver's LED’s. When set to 2 through 31, the transceiver will sleep between slots.

For example, at a setting of 2 the transceiver sleeps 1 out of 2 slots; at a setting of 3 the transceiver

sleeps 2 out of 3 slots, and so on.

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.

Setting Description

0 Lowpower, disabled

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.

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.

MPORTANT NOTES

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.

2. Additional power savings may be realized when the Number Repeaters is set to 1.

Current Draw

Less