HT3421A
Internal
Connection
CMOS
Pull-High
—
—
CMOS
Pull-High
—
CMOS
Pull-High
CMOS
Pull-High
Pin No. Pin Name I/O
15~26
27
28
29
30
31
R1~R12
TEST5
TEST2
MEMO
TEST1
RESET
I
—
—
I
—
I
Description
Matrix control key scanning inputs
For IC test only
For IC test only
Connect this pin to VSS/VDD to work in either the
memory or play mode.
For IC test only
Power on reset
At power on, the system is in the OFF state. Press
the ON/OFF key to alternate the system from OFF
to ON or vice versa. When power is auto off, there
will be no tone output for 5 minutes.
BUSY is high while the system is operating, but low
when the system is in the stand-by state.
Power supply (ground)
Toggle selection of play mode or memory mode
The system is in the play mode at power-on.
Oscillator input
Oscillator output
Memory mode indication output
Tempo indication output
Power supply (positive)
32
ON/OFF
I
33
34
35
36
37
38
39
40
BUSY
VSS
MODE
OSC1
OSC2
MLED
TLED
VDD
O
I
I
I
O
O
O
I
CMOS
—
CMOS
Pull-High
—
—
NMOS
Open Drain
NMOS
Open Drain
—
Absolute Maximum Ratings
Supply Voltage ..............................–0.3V to 5.5V
Input Voltage................. V
SS
–0.3V to V
DD
+0.3V
Storage Temperature................. –50
°
C to 120
°
C
Operating Temperature................... 0
°
C to 70
°
C
5
28th June ’96
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
