RPC-UHF RADIOMETRIX [Radiometrix Ltd], RPC-UHF Datasheet - Page 3

• Manufacturer Part Number: RPC-UHF
• Description: Radio Packet Controller
• Manufacturer: RADIOMETRIX [Radiometrix Ltd]

On receipt of a packet downloaded by the Host, the RPC will append to the packet: Preamble, start
byte and a error check code. The packet is then coded for security and mark:space balance and
transmitted through the BiM Transceiver as a 40kbit/s synchronous stream. One of four methods of
collision avoidance (listen before TX) may be user selected.
When not in transmit mode, the RPC continuously searches the radio noise for valid preamble. On
detection of preamble, the RPC synchronises to the in-coming data stream, decodes the data and
validates the check sum. The Host is then signalled that a valid packet is waiting to be unloaded. The
format of the packet is entirely of the users determination except the 1st byte (the Control Byte) which
must specify the packet type (control or data) and the packet size. A valid received packet is presented
back to the host in exactly the same form as it was given.
Additional features of the RPC include extensive diagnostic/debug functions for evaluation and
debugging of the radio and host driver software, a built in self test function and a sleep mode / wake-up
mechanism which may be programmed to reduce the average current to less than 100µA. The
operating parameters are fully programmable by the host and held in EEPROM, the host may also use
the EEPROM as a general purpose non-volatile store for addresses , routing information etc.
1.1 O
The RPC has four normal operating states:
• I
•
•
•
Radiometrix Ltd, RPC
HOST TRANSFER
TRANSMIT
RECEIVE
DLE
UNCTIONAL
PERATING STATES
To preserve versatility, the RPC does not generate routing information (i.e.
source/ destination addresses) nor does it handshake packets. These
network specific functions should be performed by the host.
I
The I
continuously searches the radio noise for message preamble. If the power saving modes have
been enabled the RPC will pulse the receiver on, check for preamble and go back to S
nothing is found. The 'ON' time is 5ms, OFF time is programmable in the RPC’s EEPROM and
can vary between 22ms and 2.9s. The TX Request line from the Host is constantly monitored
and will be acted upon if found active (low). A TX Request will immediately wake the RPC up
from S
H
If the host sets the TX Request line low a data transfer from the Host to the RPC will be
initiated. Similarly the RPC will pull RX Request low when it requires to transfer data to the
Host (this may polled or used to generate a Host interrupt ).
The transfer protocol is fully asynchronous, i.e. the host may service another interrupt and
then continue with the RPC transfer. It is desirable that all transfers are completed quickly
since the radio transceiver is disabled until the Host <> RPC transfer is completed. Typically a
fast host can transfer a 27 byte packet to / from the RPC in under 1ms.
/
DLE
OST
SLEEP
/S
DLE
T
LEEP
LEEP
RANSFERS
state is the quiescent/rest state of the RPC. In I
ESCRIPTION
mode.
DLE
the RPC enables the receiver and
LEEP
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