www.austriamicrosystems.com/RF-Transceivers/AS3900

Revision 1.00c

17 - 59

AS3900

Data Sheet - Detail ed Description

8.2.6 Data Transmit/Receive

The transmission is usually operated timer controlled in data packet mode. Packets can be sent bidirectional from 8 possible Clients to the

Master. The Clients send their packets periodically selected by the cycle time. The AS3900 is also able to provide a not timer controlled

bidirectional fast package mode, a timer controlled one way package mode and a not timer controlled one way streaming mode. The device

features auto-acknowledgement as well as automatic retransmit of lost data.

The following different communication types are possible:

One-way or bidirectional data transmission

Timer controlled or not timer controlled transmission

8.3 Link Manager

8.3.1 Establishing Network

In order to build up a star network the connections between the Master and all available Clients must be established.

8.3.1.1 Permanent Pairing

The first arrangement of the star-network is associated with the keyword “Pairing”. Basically the ID of the available Clients are transmitted to the

Master, because first all Clients are unknown for the Master. This is accomplished by sending a Wakeup signal from the Master to the Clients, so

that all Clients exit from standby-mode. All Clients are woken up and answer after a random delay with the first data packet that includes the

unique identification number (ID). The Master receives the packets from the different Clients after random time delays (set by MCU). After MCU

verification the ID’s are stored in the Master’s ID registers.

After that the Clients are paired to the Master and switched to Power-down mode. See detailed description in 8.6 Pairing.

8.3.1.2 Wakeup and Data Transmit/Receive

For transmitting data it is necessary to follow the listed procedure. First all Clients have to be set to Standby mode (periodically listen for Wakeup

signal). Then the Master sends a “Wakeup” signal to exit all Clients from Standby mode. With this wakeup signal, all Clients are synchronized

and send the timing information to the Master. Once synchronized, the whole communication is controlled by the Link manager in Auto-

acknowledge mode. See detailed description in chapter 8.7 Transmission Modes.

The communication between the Master and up to eight Clients is timer controlled. Figure 8 shows the communication between 1 Master and 3

Clients. The cycle time is adjustable via the register map. The data rate and the frequency deviation must be the same for all members of the star

network.

Figure 12. Time Division Multiplexing Principle

MASTER

time

TX ON

RX ON

CLIENT1

time

CLIENT2

time

CLIENT3

time

CYCLE TIME CLIENT1

CYCLE TIME CLIENT2

CYCLE TIME CLIENT3

TX ON

RX ON

TX ON

RX ON

TX ON

RX ON