Silan
Semiconductors
SC6122
Pull-down resistors are connected between the Key Input and Vss Pins. When more than one key (except the
double key combinations:K21+22, K21+23, K21+24) are pressed simultaneously, the transmission output stops.
Two key inputs are regarded as being pressed simultaneously when the time interval between these two key
entries is less than 36ms.
The order of priority given to two key inputs with a time interval of more than 36ms is on a First-Pressed-First-
Served or Longer-Pressed-First-Served Basis.
When a key is pressed, the custom and data codes are read. 36ms later, the Remote (REM) Output is activated.
When the key is kept depressed during this 36ms, one transmission is outputted. If the key is depressed for more
than 108ms, then the only the leader code is transmitted continuously.
4. DOUBLE KEY OPERATION
Double Key Operation is useful for operations such as tape deck recording. The following table shows the Key
Data corresponding to the double keys pressed. Also refer to the Key Input Section.
The Double Key operation forms are as follows:
Ke y
D0
1
D1
0
D2
1
D3
0
D4
1
D5
1
D6
0
D7
0/1
0/1
0/1
K21+K22
K21+K23
K21+K24
0
1
1
0
1
1
0
1
1
1
0
1
1
0
Note: D7=1 when SEL is connected to VSS, or D7=0 when SEL is connected to VDD.
D5+K22 to 24
Transmission
OPERATION
K21
push
K21 Transmission
t >126ms
K22 to 24
push
NO OPERATION
K21
K21 Transmission
36ms< t <126ms
No Transmission
K22 to 24
NO OPERATION
K21
No Transmission
-36ms< t < 36ms
K22 to 24
NO OPERATION
No Transmission
K21
t >126ms
K22 to 24
K22 to 24 Transmission
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 2.2
2002-03-01
5
SILAN [ SILAN MICROELECTRONICS JOINT-STOCK ]
