Pin Descriptions
Pin name
Pin No.
Type
LC72121MA
Function
Equivalent circuit
XIN
XOUT
1
X’tal OSC
• Crystal oscillator element connections (4.5 or 7.2 MHz)
24
FMIN
AMIN
CE
DI
CL
DO
VDD
VSSX
VSSd
BO1
BO2
BO3
BO4
IO1
IO2
• FMIN is selected when DVS in the serial data is set to 1.
• Input frequency: 10 to 160MHz
• The signal is passed through an internal divide-by-two prescaler and
Local oscillator
17
then input to the swallow counter.
signal input
• The divisor can be set to a value in the range 272 to 65535. Since the
internal divide-by-two prescaler is used, the actual divisor will be
twice the set value.
• AMIN is selected when DVS in the serial data is set to 0.
• When SNS in the serial data is set to 1:
• Input frequency: 2 to 40MHz
• The signal is input to the swallow counter directly.
• The divisor can be set to a value in the range 272 to 65535. The set
Local oscillator
16
value becomes the actual divisor.
signal input
• When SNS in the serial data is set to 0:
• Input frequency: 0.5 to 10MHz
• The signal is input to a 12-bit programmable divider directly.
• The divisor can be set to a value in the range 4 to 4095. The set
value becomes the actual divisor.
• This pin must be set high to enable serial data input (DI) or serial data
3
Chip enable
S
output (DO).
4
Input data
• Input for serial data transferred from the controller
S
• Clock used for data synchronization for serial data input (DI) and
5
Clock
S
serial data output (DO).
• Output for serial data transmitted to the controller. The content of the
6
Output data
data transmitted is determined by DOC0 through DOC2.
18
Power supply • LC72121MA power supply (VDD 2.7 to 3.6V)
-
• The power on reset circuit operates when power is first applied.
2
Ground
• Ground for the crystal oscillator circuit
-
• Ground for the LC72121MA digital systems other than those that use
15
Ground
-
VSSa or VSSX.
• Output-only ports
• The output state is determined by BO1 through BO4 in the serial data.
7
When the data value is 0: The output state will be the open circuit
8
Output port
state.
9
When the data value is 1: The output state will be a low level.
10
• A time base signal (8Hz) is output from BO1 when TBC in the serial
data is set to 1.
• Shared function I/O ports
• The pin function is determined by IOC1 and IOC2 in the serial data.
When the data value 0: Input port
When the data value 1: Output port
• When specified to function as an input port:
The input pin state is reported to the controller through the DO pin.
11
When the input state is low: The data will be 0:
I/O port
14
When the input state is high: The data will be 1:
• When specified to function as an output port:
The output state is determined by IO1 and IO2 in the serial data.
When the data value is 0: The output state will be the open circuit
state.
When the data value is 1: The output state will be a low level.
• These pins are set to input mode after a power on reset.
Continued on next page.
No.A2009-6/24