Silan
Semiconductors
SC2128A
the final adjustments, regardless the adjustments are made from panel key or from remote control handset. One
exception is the SLEEP key available on the remote control handset. SLEEP key start or adjusts the fan to the
default sleep settings. Regardless the fan is started by SPEED or by MEMS, SLEEP key does not affect the
operation memory.
14. BUZZER OUTPUT
All valid key pressed except OFF/MEMS initiates a 150ms
duration 4kHz 50% duty cycle pulse train at OFF/MEMS/BUZZ
pin. OFF/MEMS key function as OFF key if pressed when fan is
in any on state. In this case, it does NOT initiate an output on
BUZZ. OFF/MEMS key functions as MEMORY-START key if
pressed when fan is in off state. In this case, it DOES initiate a
150ms duration 4kHz 50% duty cycle pulse train on BUZZ. Note
that when OFF/ MEMS/BUZZ outputs the pulse train, key input
is suppressed. That is, pressing OFF/MEMS key when the
buzzer is buzzing is NOT recognized by SC2128A. The
diagram right shows the buzzer connection.
V
SS
-5V
V
DD
SC2128A
OFF/MEMS/
BUZZ
OFF/MEMS key
15. REMOTE CONTROL DECODER
SC2128A is designed to be used together with SC2268 infrared ray remote control encoder. Such combination
allows up to 8 remote control keys – SPEED, MODE, TIMER, LIGHT, SLEEP, SW1, SW2, OFF/MEMS – to be
built on the remote control handset. 4 bits customer code, b3 ~ b6, is encoded by SC2268 and decoded by
SC2128A in order to avoid remote control contention between devices. With SC2268, b3 is determined by
bonding option; b4, b5 and b6 are determined by connecting respective c4, c5, c6 pin to V
DD
or V
SS
. With
SC2128A, b3 and b6 can be mask programmed upon customer request and with NRE.
The remote control signal coding scheme is fully
compatible with SC2268. Some description follows.
Please refer to specification of SC2268 for details.
When SC2128A receives a remote control signal at
its REMOTE pin, it decodes the received waveform
into consecutive “0” bits and “1” bits. It first
compares the received start word against its
customer code. If and only if the start word matches
the customer code, it then compares for two
consecutive and matched code words. It then
actuates the command according to the code words
table shown later.
Code frame
start word
1st code word 2nd code word
Start/Code word:
b0
b1
b2
b3
b4
b5
b6
b7
"0" bit:
Code bit:
"1" bit:
0.625ms
1.875ms
2.5ms
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
11
SILAN [ SILAN MICROELECTRONICS JOINT-STOCK ]
