Differential Manchester encoding coverts the 0000 into 11001100 which is the bit pattern equivalent to preamble
required to settle adaptive data slicer in the RF receiver module.
Preamble =
Sync1 =
Sync2 =
DataA =
DataB =
Address =
Checksum =
11001100
this byte is not decoded.
10111111
111100(A7)(B7)
0(DA6-DA0)
0(DB6-DB0)
0(A5-A0)0
sum of (DA7-DA0) + (DB7-DB0) + Adr(whole byte) truncated to 8 bits
This allows 6 bits of address and 2 data bytes per 60ms burst when 3.58MHz resonator is used.
Preamble
00000000000000
11001100
Sync1
10111111
Sync2
111100(DA7)(DB7)
Data A
0(DA6:DA0)
Data B
0(DB6:DB0)
Address
0(A5:A0)0
Check Sum
DA7:DA0+DB7:DB0
+A7:A0
Postamble
0000
Figure 6: Control124 data packet
In the following example, Control124 in Encoder mode is set with the following.
DA7
DA6
DA5
DA4
DA3
DA2
DA1
DA0
DB3
DB2
DB1
DB0
A3
A2
A1
A0
0
1
1
0
1
0
0
1
1
0
1
0
1
0
0
1
The Control124 will packetise the address and data into the following format.
Preamble
11001100
Sync1
10111111
Sync2
11110010
Data A
01101001
Data B
00001010
Address
00010010
Checksum
10000101
Postamble
0000
Figure 7: Synchronisation codes, DataA, DataB, Address, Checksum and Postamble
Radiometrix Ltd
Control124
page 5
RADIOMETRIX [ RADIOMETRIX LTD ]
