Rx Frames Format; L : Length Field; C : Control Field; M: Manufacturer Id Field - ADEUNIS AMR Range Mode D'emploi

DONGLE USB WMBUS AMR - Mode d'emploi - User guide V1.3

4.3.1 Rx frames format

Upon receipt of a radio frame, the DONGLE USB AMR transmits data over the USB port with the following format :
0xFF Length
1 Bytes 1 byte
Wake-up Byte sent
in USB mode from
Define the length
Dongle USB AMR to
in Bytes of the Data
Host. This wake-up
section. Maximum
byte can be use to
length is 138.
wake-up the host if
needed.
This Length is set to
In SPI mode, this bit
0, in case no frame
is not available, the
has been received
host read directly
the ACK/NACK.

4.3.2 L : Length field

Length field (L = 0 to 255), which signals the total number of user bytes (excluding the length field and the CRC's).

4.3.3 C : Control Field

For transmit only devices (S1, T1 mode) the Cfield value C=0x44 (send-no-Reply)
In bidriectional mode, the C-field is managed by the module.

4.3.4 M: Manufacturer ID Field

User/manufacturer unique ID of the meters.
If M=ARF, the user/manufacturer must guarantee worldwide uniqueness address. Otherwise, the address is unique at least within maximum
transmission range.

4.3.5 A : Address

Unique address, user/manufacturer must guarantee it.

4.3.6 CI : Control Information Field

Must be set according to EN13757-3.
Examples :
• 0x72 M-Bus Application Layer with full header
• 0x78 M-Bus Application Layer without header, to be defined
• 0x7A M-Bus Application Layer with short header
• ...

4.3.7 CRC: Cyclic Redundancy Check

The CRC is computed over the information from the previous block, with the following polynomial formula: x16+x13+x12+x11+x10+x8+x6+x
5+x2+1 (initial value = 0)
Please note: The repeater or Multiple addressing roles (CI = 0x81) are not covered with this summary. Please refer to EN13757-4:2005 stan-
dard.
C M & A
1 Byte 2 + 6 Bytes
WMBUS Manu-
WMBUS C Field
facturer ID and
in the Rx received
Address of WMBUS
frame
received frame
CI Data
From 1 Byte to 138
1 Byte
Bytes
WMBUS CI Field
Data received.
in the Rx received
138Bytes max.
frame
RSSI
1 Byte
RSSI Level of Rx
Frame.
0 => -125dBm
1 => -124,5dBm
X => -125 + x*0,5
dBm
255 => 2,5dBm
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