rpc2a-000-dil Radiometrix Ltd, rpc2a-000-dil Datasheet - Page 3

• Manufacturer Part Number: rpc2a-000-dil
• Description: Uhf Radio Packet Controller
• Manufacturer: Radiometrix Ltd

On receipt of a packet downloaded by the Host, the RPC2A 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 BiM2A Transceiver as a 64kbps synchronous stream. One of four methods of
collision avoidance (listen before TX) may be user selected.
When not in transmit mode, the RPC2A continuously searches the radio noise for valid preamble. On
detection of preamble, the RPC2A 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 RPC2A 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 100 A. 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 RPC2A has four normal operating states:
Radiometrix Ltd, RPC2A
I
HOST TRANSFER
TRANSMIT
RECEIVE
UNCTIONAL
DLE
PERATING STATES
To preserve versatility, the RPC2A 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
and continuously searches the radio noise for message preamble. If the power saving modes
have been enabled the RPC2A will pulse the receiver on, check for preamble and go back to
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
RPC2A up from S
H
If the host sets the TX Request line low a data transfer from the Host to the RPC2A will be
initiated. Similarly the RPC2A 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 RPC2A transfer. It is desirable that all transfers are completed quickly since
the radio transceiver is disabled until the Host <> RPC2A transfer is completed. Typically a fast
host can transfer a 27 byte packet to / from the RPC2A in under 1ms.
/
DLE
LEEP
OST
SLEEP
/S
DLE
T
LEEP
if nothing is found. The 'ON' time is 5ms, OFF time is programmable in the RPC2A’s
RANSFERS
state is the quiescent/rest state of the RPC2A. In I
ESCRIPTION
LEEP
mode.
DLE
the RPC2A enables the receiver
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