Typical Application Circuit
5V
supply
Push-to-Learn
MODE
RXD
NC
LRN
LED-L
NC
RST
Vss
S0
S1
S2
S3
RXD
Vcc
470R
1k
RF
NC
Vdd
NC
100nF
470R
470R
470R
470R
NC
GND
470R
LED-V
NC
Figure 2: KRX416 Function-Code display - example circuit
Pin
1
Name
LRN
Input/Output
Input
Description
Normally held-high: Momentarily connect to 0V to enter Learn Mode
– stays in Learn Mode until a compatible Radiometrix transmitter is
successfully learned or time-out occurs in approx. 18s.
Connect to 0V for more than 10s (approx.) to clear NV memory: this
removes all learnt transmitters.
Active high during Learning Phase – A code-hopping transmitter is
Learnt during this time by receiving and decoding its transmission.
Pin 2 then cycles low-high-low for a short period (flashes the LED) to
indicate that a transmitter has been Learned.
2
LED-L
Output1
If Pin 1 is held low >10s Pin 2 goes low then momentarily high again
(when Pin 1 returned high) to indicate NV Memory has been cleared.
Active high (10ms or for as long as S0-S3 are active) when not in
Learn Mode to indicate that the IC has decoded a Function Code (S0-
S3 state) that was used previously in Learning a Transmitter.
Do not connect anything to this pin
Normally held high. Taken low this pin will Reset the IC. The NV
Memory is unaffected.
3
4
NC
RST
-
Input
5
6
Vss
S0
Supply
Supply Ground
Output1
Function Code output S0 – active high 10ms pulse2 or a 350-500ms
pulse and held high for repeat messages (see “Mode” description)
Function Code output S1 – operation as above
7
8
9
10
11
S1
S2
S3
NC
LED-V
Output1
Output1
Output1
-
Function Code output S2 – operation as above
Function Code output S3 – operation as above
Do not connect anything to this pin
Active high when the received message indicates that the
Transmitter encoder power supply is below 3.8V (approx.)
Do not connect anything to this pin
4.5-5.5V supply (decouple with 0.1µF close to IC)
Do not connect anything to this pin
Output1
12, 13
14
15, 16
NC
Vdd
NC
-
Supply
-
17
18
RXD
MODE
Input
Data input from receiver, also connect to Vdd via 10k (no input =1)
Can be held high or low. When high, outputs S0-S3 are active only
for a brief period but when Mode is held low a “latency” is effected.
Input3
Radiometrix Ltd
KRX416
page 2
RADIOMETRIX [ RADIOMETRIX LTD ]
