Radiometrix
Hartcran House, 231 Kenton Lane, Harrow, HA3 8RP, England
Issue: 2, 13 February 2007
Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233
Control124
4 bit Address - 12 bit Data encoder/decoder
Control124 is a 4 bit address, 12 bit data
encoder and decoder combined in a single IC.
This device can operate in either Encode or
Decode mode. It uses 1kbps differential
Manchester bit balancing with preamble and
checksum. CTR124 is specifically designed to
be used in RF remote control applications. It
is available in 28pin SO and DIL packages.
Figure 1: Control124 in 28 pin DIL package
Features
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Operating voltage (temperature):
4.0V-5.5V for standard version (-40°C to +125°C)
2.0V-5.5V for low voltage version (-40°C to +85°C)
Draws <2mA without external load
4 bit address and 12 bit data
16 different remotes with 12 controls each
Single packetised transmission for fast activation
Maximum usage of the range capability of an RF module
Adequate preamble to settle data slicer in the receiver.
Extra wake up preamble to allow for transmitter power up time requirements
Differential Manchester encoding of address, data and checksum
Synchronisation codes and checksum to reduce false triggering on noise
Suitable to be used with Narrow Band FM radio modules
Ceramic resonator or crystal oscillator up to 20MHz
Data rate up to 5.6kbps
Minimum external component requirement
4 wire, push button and latched push button modes
Custom address, data bit variations available subject to minimum order quantity
Applications
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Security and Alarm systems
Emergency assistance call system
Status reporting and monitoring systems
RF Remote control systems
Industrial controls
HVAC controls
Simple On/Off switching
Long range telecontrol with Narrow Band FM radios
Radiometrix Ltd
Control124
page 1
Encoder Mode
Control124 can be put into Encoder Mode by connecting Mode (pin 2) to supply.
5V
supply
10k
10k
Transmitter
10k
10k
Vcc
GND
10k
10k
10k
10k
4k7
TXE
NC
Vss
OSC1
OSC2
DA0
DA1
DA2
DA3
10k
10k
RF
TXD
RST
SEND
TXD
NC
MODE
DB3
DB2
DB1
DB0
A3
A2
A1
A0
Vdd
Vss
DA7
DA6
DA5
DA4
Contro124
100nF
3.58MHz
Figure 2: Control124 in Encoder Mode
Pin
1
2
3
4
5
6
7
8
9
10
11 - 18
19
20
21 - 24
25 - 28
Name
RST
SEND
TXD
NC
MODE
TXE
NC
VSS
OSC2
OSC1
DA0 - DA7
VSS
VDD
A0 - A3
DB0 - DB3
Input/Output
Input
Input
Output
-
Input
Output
-
Supply
Output
Input
Input
Supply
Supply
Input
Input
Description
Active Low Reset (Connect to user system reset or tie to Vdd)
Active Low Send Packet (Encoder Enable)
1
Encoded Address and Data to TXD input of RF Transmitter
-
RX=0V, TX=Vdd (no pull-up, only read at reset/power up)
Active Low RF Transmitter Enable (Open drain, require 10k pull-up)
2,3
-
Supply Ground
3.58MHz resonator
4
3.58MHz resonator
4
8 bits of Data A; Schmitt trigger input
5, 6
Supply Ground
4.0V-5.5V supply (decouple with 100nF close to IC).
2.0V-5.5V (low voltage version)
Least significant 4 bits of Address (Internal pull-ups to Vdd)
6
Least significant 4 bits of Data B (Internal pull-ups to Vdd)
6
Notes:
1. If a low going pulse of between 10µs and 50ms is applied to SEND pin then a single packet will
be transmitted
2. After asserting TXE low (active), the encoder allows 55ms for NBFM TX to power up and settle
3. TXE is an open drain output (no pull-up). Connect it to Vdd via a 10kΩ pull-up resistor
4. OSC1,2 require a 3.58MHz ceramic resonator with internal capacitors like Murata
CSTLA3M58G55-B0. If a 2 pin resonator or crystal is used, then two 15pF-22pF caps are
needed: one from OSC1 to 0V another from OSC2 to 0V. 100Ω series resistor between OSC2 and
crystal may be required when driving low frequency crystal with High Speed (H) CTR124H
version.
5. Not suitable for non-standard logic levels, require external pullup resistors.
6.
Absolute maximum source/sink current from each DA0-DA7, DB0-DB3 and A0-A3 pins is 25mA.
Absolute maximum total current from DA0-DA7 port and DB0-DB3, A0-A3 port is 200mA
7.
MODE pin is only read at reset/power up. Connect to either Vdd (Encoder) or 0V (Decoder).
8.
Without external loads the CTR124 draws <2mA from 5V supply
9.
Standard version can be used down to 4V for <20MHz oscillator.
Low voltage version can be used down to 2V for <4MHz oscillator
Radiometrix Ltd
Control124
page 2
Decoder Mode
Control124 can be put into Decoder Mode by connecting Mode (pin 2) to Ground.
5V
supply
10k
RF
RXD
Receiver
470R
Vcc
GND
3.58MHz
RST
LATCH
RXD
STB
MODE
NC
NC
Vss
OSC1
OSC2
DA0
DA1
DA2
DA3
DB3
DB2
DB1
DB0
A3
A2
A1
A0
Vdd
Vss
DA7
DA6
DA5
DA4
470R
470R
470R
470R
Contro124
100nF
470R
470R
470R
470R
470R
470R
470R
470R
Figure 3: Control124 in Decoder Mode
Pin
1
2
3
4
5
6
7
8
9
10
11 - 18
19
20
21 - 24
25 - 28
Name
RST
LATCH
RXD
STB
MODE
NC
NC
VSS
OSC2
OSC1
DA0 - DA7
VSS
VDD
A0 - A3
DB0 - DB3
Input/Outp
ut
Input
Input
Input
Output
Input
-
-
Supply
Output
Input
Output
Supply
Supply
Input
Output
Description
Active Low Reset (Connect to user system reset or tie to Vdd)
0V = latch DA3:D0 until next packet
Vdd = clear DA3:DA0 after 150ms (no pull-up)
Encoded Address and Data from RXD Output of RF Receiver
Positive going pulse on reception of valid data packet. 10µs duration
RX=0V, TX=Vdd (no pull-up, only read at reset/power up)
-
-
Supply Ground
3.58MHz resonator
1
3.58MHz resonator
1
8 bits of Data A
2
Supply Ground
4.5-5.5V supply (decouple with 0.1µF close to IC)
2.0V-5.5V (low voltage version)
Least significant 4 bits of Address (Internal pull-ups to Vdd)
2
Least significant 4 bits of Data B
2
Notes:
1. OSC1, 2 require a 3.58MHz ceramic resonator with internal capacitors like Murata
CSTLA3M58G55-B0. If a 2 pin resonator or crystal is used, then two 15pF-22pF caps are
needed: one from OSC1 to 0V another from OSC2 to 0V. 100Ω series resistor between OSC2 and
crystal may be required when driving low frequency crystal with High Speed (H) CTR124H
version.
2.
Absolute maximum source/sink current from each DA0-DA7, DB0-DB3, A0-A3 pins is 25mA
Absolute maximum total current from DA0-DA7 port and DB0-DB3, A0-A3 port is 200mA
3. MODE pin is only read at reset/power up. Connect to either Vdd (Encoder) or 0V (Decoder).
4. Without external loads the CTR124 draws <2mA from 5V supply.
5. Standard version can be used down to 4V for <20MHz oscillator.
Low voltage version can be used down to 2V for <4MHz oscillator.
6. High Speed, CTR124H, version should not be used with Narrow Band FM radio modules.
Radiometrix Ltd
Control124
page 3
Encoded Data Packet Format
Transmission format is 1kbps differential Manchester encoding when using 3.58MHz resonator.
Oscillator frequency can decreased to suit narrow band RF module data rate requirements. CTR124H
IC running at 20MHz can be used with wideband radio modules for fast data transmission.
0
0
0
1
0
1
0
1ms
1
500µs
1
Figure 4: 1kbps differential Manchester coding of ‘1’ and ‘0’
Control124 transmits a 6-byte burst, with 8 bits of preamble and 4 bits postamble. When firing up the
transmitter from cold Control124 puts in an extra 55ms especially for Narrow Band FM transmitter
and receiver requiring longer power-up to stable data time.
Figure 5: Push button transmission with 55ms power-up preamble
The large amount of sync code, address and checksum reduce the likelihood of false calling on noise to
an insignificant degree, while the breaking up of the data sequences with bit7 zeros is to reduce the
likelihood of the decoder mistaking particular sequences in the data for sync codes.
Radiometrix Ltd
Control124
page 4
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
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