XTR-8LR-USB
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User Manual
The technical features can change without forecasting. AUR°EL S.p.A doesn’t assume any responsability of demage due to the improper use of the device.
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AUR°EL S.p.A.
Via Foro dei Tigli, 4 - 47015 Modigliana (FC) – ITALY
Tel.: +39.0546.941124 Fax: +39.0546.941660
http://www.aurelwireless.com
- email:
Rev 1.3 18/11/2019
Page
15
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17
The absence of data towards the usb is given by a Timeout ( equal to the 2 serial byte time based on the data
rate ); expired it the transceiver does not memorize other data in input until the whole data forwarding inside
the radio buffer.
Max packet size is 247 bytes ( S10=1 register ) in the addressing NORMAL modality and 255 byte ( S10=0
register ) in the not addressing NORMAL modality.
Data are sent on air only when the UART storage phase is over. Microcontroller checks the incoming
packets from radio receiver and enables forwarding to UART output port only in case of valid packets
(corrupted packets are eliminated).
RTS line is helpful to monitor UART buffer status: it's normally low level and goes high when buffer is full
or during emptying of UART buffer towards radio buffer, or when data are sent on TX_UART.
In order to grant a proper functionality of the transceiver, it's not allowed to overlap phases: i.e. if unit
is emptying UART buffer to radio buffer, any data incoming from USB port are lost.
Likewise is not allowed to receive data from RF until the previous packet is still to be transmitted
through USB port.
Furthermore consider that USB reception has priority over radio reception : when a byte is received
from USB the radio reception in stopped and the device waits until the USB packet is completed.
Therefore in that phase eventually radio data are lost.
In order to execute properly the exchange of packet from/to UART port, it's recommended to control
the RTS line as go/stop operation signal.
Using the NORMAL mode with addressing:
NORMAL mode allows to work with addressing data packet, so a potential network composed by many
devices permit a point-to-point communication, or point-multipoint.
From command-mode network function is achievable with
ATS10=1
resigter, other registers to be setted are
NETWORK ID reg.number S11 and SOURCE ADDRESS S12 (2 bytes) a unique identifier for each device.
A wireless network could be composed by 2 to 65536 devices. SOURCE ADDRESS identifies from which
device the message starts, DESTINATION ADDRESS identifies who is the device to which the message is
meant. From this condition the device forwards on UART the radio data packet received, but only those who
have the same NETWORK ID and DESTINATION ADDRESS. When the device transmit the
DESTINATION ADDRESS must be applied ever before the payload.
In case of point –multipont network, it’s necessary to set up the DESTINATION ADDRESS on FFFF, then
all the related devices with same NETWORK ID will receive the payload preceded by 0xFFFF.
No automatic messages ACK is provided.
