Radiometrix Ltd, RPC2A

page 9

Data packets are sent to / received from remote RPC2A’s. They begin with a control byte with bit 7

cleared and may be of variable length and contain up to 27 bytes of user determined data.

The remainder of the bytes in the data packet are of the users determination.

The packet would usually be made up of a number of fields consisting of some

but not necessarily all of the following :-

Source address / ID

Destination address / ID

System ID

Packet count

Encryption / Scrambler control

Additional error check codes ( The RPC2A performs it's own error checks)

Routing information ( for repeaters)

Link control codes (connect/disconnect/ACK/NAK etc.)

Data field

The RPC2A’s EEPROM memory can be accessed by setting bit 7 in the control byte. Bit 6 (R/W flag)

defines a memory read or write. The bits left define the address.

Write to memory

Read from memory

10

Address (6 bit)

0

7

6

RPC2A

RPC2A

Data Byte

Control Byte

Data byte

0

7

10

Address (6 bit)

0

7

6

Control Byte

figure 9: Control byte for data packet

figure 10: RPC2A memory access