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
RADIOMETRIX [ RADIOMETRIX LTD ]
