Pin Assignment

Pin Description

Pin No.

Pin Name

I/O

Description

1~4

SW0~SW3

I

4-bit general purpose input port

Whether these pins are used or not, they should be connected to VDD

or VSS.

5DO

O

Output serial data at the falling edge of the shift clock, starting from low

order bit. This is an NMOS open-drain output pin.

6DI

I

Input serial data at the rising edge of the shift clock, starting from the

low order bit.

7, 43

VSS

¾

Negative power supply, ground

Both of the VSS (pin 7 and pin 43) should be connected to ground.

8

CLK

I

Reads serial data at the rising edge, and outputs data at the falling

edge.

9CS

I

Initializes serial interface at the rising or falling edge of the HT16512.

Then it waits to receive a command. Data input after CS has fallen is

processed as a command. While command data is processed, current

processing is stopped, and the serial interface is initialized. While CS

is high, CLK is ignored.

10~13

K0~K3

I

Keying data input to these pins is latched at the end of the display cy-

cle.

14, 38

VDD

¾

Posistive power supply

15~20

S0/K0~S5/K5

O

Segment or key source output pins (dual function). This is PMOS

open-drain and pull-low resistor output.

21~25

S6~S10

O

Segment driver output pins (segment only). This is PMOS open-drain

and pull-low resistor output.

26, 28~31

S11/G10~S15/G6

O

Segment or Grid driver output pins. These pins are selectable for seg-

ment or grid driving. This is PMOS open-drain and pull-low resistor

output.

27

VEE

¾

VFD power supply

37~32

G0~G5

O

Grid driver output pins (Grid only). This is PMOS open-drain and

pull-low resistor output.

42~39

LED0~LED3

O

LED driver output ports. This is a CMOS output pin.

44

OSC

I

Connected to an external resistor or an RC oscillator circuit.

HT16512

Rev. 1.40

2

May 3, 2005

H T 1 6 5 1 2

4 4 Q F P - A

1

2

3

4

5

6

7

8

9

1 0

1 1

1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0 2 1 2 2

2 3

2 4

2 5

2 6

2 7

2 8

2 9

3 0

3 1

3 2

3 3

3 4

3 5

3 6

3 7

3 8

3 9

4 0

4 1

4 2

4 3

4 4

S W 0

S W 1

S W 2

S W 3

D O

D I

C L K

C S

K 0

K 1

V S S

S 8

S 9

S 1 0

S 1 1 / G 1 0

S 1 2 / G 9

S 1 3 / G 8

S 1 4 / G 7

S 1 5 / G 6

G 5

G 4

V E E