Pad Description

Pad No.

Pad Name

I/O

Description

1~33

87~149

SEG63~SEG95

SEG0~SEG62

O

LCD segment outputs

34~49

71~86

COM31~COM16

COM0~COM15

O

LCD common outputs, under 112

´16 command mode, COM16~COM31 will

share to SEG96~SEG111. COM31/SEG96, COM30/SEG97, COM29/

SEG98....., COM18/SEG109, COM17/SEG110, COM16/SEG111

50

CS

I

Chip selection input with pull-high resistor. When the CS is logic high, the

data and command read from or write to the HT1660 are disabled. The serial

interface circuit is also reset. But if the CS is at a logic low level and is input to

the CS pad, the data and command transmission between the host controller

and the HT1660 are all enabled.

51

RD

I

READ clock input with pull-high resistor. Data in the RAM of the HT1660 are

clocked out on the falling edge of the RD signal. The clocked out data will ap-

pear on the data line. The host controller can use the next rising edge to latch

the clocked out data.

52

WR

I

WRITE clock input with pull-high resistor. Data on the DATA line are latched

into the HT1660 on the rising edge of the WR signal.

53~56

DB0~DB3

I/O

Parallel data input/output with a pull-high resistor

57

VSS

¾ Negative power supply for logic circuit, ground

58

59

OSCI

OSCO

I

O

The OSCI and OSCO pads are connected to a 32.768kHz crystal in order to

generate a system clock. If the system clock comes from an external clock

source, the external clock source should be connected to the OSCI pad. But

if an on-chip RC oscillator is selected, the OSCI and OSCO pads can be left

open.

60

VDD

¾ Positive power supply for logic circuit

61

VLCD

I

Power supply for LCD driver circuit

62

IRQ

O

Time base or Watchdog Timer overflow flag, NMOS open drain output.

63, 64

BZ, BZ

O

2kHz or 4kHz frequency output pair (tristate output buffer)

65~69

T1~T4, T000

I

Not connected

Absolute Maximum Ratings

Storage Temperature ............................

-50°Cto125°C

Operating Temperature...........................

-25°Cto75°C

Note: These are stress ratings only. Stresses exceeding the range specified under

²Absolute Maximum Ratings² may

cause substantial damage to the device. Functional operation of this device at other conditions beyond those

listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliabil-

ity.

HT1660

Rev. 1.00

5

September 16, 2003