HT1625
Pad Description
Pad No.
1
Pad Name
RD
I/O
I
Description
READ clock input with pull-high resistor. Data in the RAM of the
HT1625 are clocked out on the rising edge of the RD signal. The
clocked out data will appear on the data line. The host controller
can use the next falling edge to latch the clocked out data.
WRITE clock input with pull-high resistor. Data on the DATA
line are latched into the HT1625 on the rising edge of the WR sig-
nal.
Negative power supply, Ground
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 se-
lected instead, the OSCI and OSCO pads can be left open.
Positive power supply
LCD operating voltage input pad.
Time base or Watchdog Timer overflow flag, NMOS open drain
output
2kHz or 4kHz tone frequency output pair
Not connected
LCD common outputs
LCD segment outputs
Chip selection input with pull-high resistor. When the CS is logic
high, the data and command read from or write to the HT1625
are disabled. The serial interface circuit is also reset. But if the
CS is at logic low level and is input to the CS pad, the data and
command transmission between the host controller and the
HT1625 are all enabled.
2
3
4
5
6
7
8
9
10, 11
12~14
15~22
23~86
WR
DATA
VSS
OSCI
OSCO
VDD
VLCD
IRQ
BZ, BZ
T1~T3
COM0~COM7
SEG0~SEG63
I
I/O Serial data input/output with pull-high resistor
¾
I
O
¾
I
O
O
I
O
O
87
CS
I
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 125°C
Operating Temperature ..............-25°C to 75°C
Note: These are stress ratings only. Stresses exceeding the range specified under
²Absolute
Maxi-
mum 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 expo-
sure to extreme conditions may affect device reliability.
5
April 21, 2000
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
