Silan

Semiconductors

SC8521

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

REV: 1.3

2002.03.01

4

(Continued)

Pin No.

Symbol

Description

17

DR6

Drive line 6 for key matrix (active LOW)

18

Ground

19

Lout

Output signal

20

Power supply

FUNCTION DESCRIPTION

1. Key numbering for matrix is given in tables 1

Table1

key numbering for 20-pin package

Sense lines

Driver lines

SN0

SN7

SN1

SN2

SN3

SN6

SN4

SN5

DR5

0:BANK0

1

2

3

4

5

6

7

DR4

8:BANK1

9

101112

1314

15

DR3

16:BANK2

17

18

19

20

21

22

23

DR2

24:BANK3

25

26

27

28

29

30

31

DR1

32:BANK4

33

34

35

36

37

38

39

DR0

40:BANK5

41

42

43

44

45

46

47

DR6

48:BANK6

49

50

51

52

53

54

55

SN0 connected GND, send BANK7 code. BANK0----7 see the following code table.

When the keys have been scanned the key-number of the activated key serves as the address of the ROM to

obtain the required codeword. Consequently, key numbers 6, 7, 14, 15, 22, 23, 30, 31, 38, 39 and 40 to 55 will not

be addressed.

The ROM contains 8 banks of 64 code words. Thus for each key a maximum of 8 different code words may be

generated. With multi-system use, 8 different systems (e.g. TV, VCR, tuner, CD etc.) may be selected. Apart from

the system bits the command bits may also be different in different banks (true multi-function keys). Selection can

be performed using the keys. For each key three bank selected bits are present that determine which bank will be

selected for the next key.

For each key an ‘inhibit’ bit is also present. When this bit is at logic 1 at an address in a given bank, and when

the corresponding key is pressed (when this bank has been selected) no transmission will take place.

A single system option is available however, whereby instead of keys jumper wire and/or a switch may be used

for bank selection. Using this option it is possible to program different transmitter models in one IC and select the

required bank by means of jumper wire. Instead of a jumper wire a side-switch may also be used to change the