HT1625
Pad Description
Pad No.
Pad Name
I/O
Description
READ clock input with pull-high resistor. Data in the RAM of the HT1625 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.
WRITE clock input with pull-high resistor. Data on the DATA line are latched
into the HT1625 on the rising edge of the WR signal.
Serial data input or output with pull-high resistor
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 selected 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.
1
RD
I
2
3
4
5
WR
DATA
VSS
OSCI
I
I/O
¾
I
6
OSCO
O
¾
I
O
O
I
O
O
7
8
9
10, 11
12~14
15~22
23~86
VDD
VLCD
IRQ
BZ, BZ
T1~T3
COM0~COM7
SEG0~SEG63
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
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.
Rev. 1.10
5
September 11, 2002
ETC [ ETC ]
