HMS87C1808B Datasheet, PDF (76/99 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

HMS87C1X04B/08B/16B
INPUT PIN
V_DD
V_DD
internal
pull-up
i
GND
V_DD
X
Weak pull-up current flows
V_DD
O
OPEN
O
INPUT PIN
OPEN
i
V_DD
i=0
O
Very weak current flows
X
i=0
GND
O
When port is configure as an input, input level should
be closed to 0V or 5V to avoid power consumption.
Figure 18-7 Application Example of Unused Input Port
OUTPUT PIN
ON
OFF _i
GND
X
ON
OPEN
OFF
O
V_DD
ON
O ^OFF
In the left case, much current flows from port to GND.
OUTPUT PIN
ON
V_DD
L
OFF
V_DD
L
OFF _i
GND
ON i=0
GND
X
O
In the left case, Tr. base current flows from port to GND.
To avoid power consumption, there should be low output
to the port.
Figure 18-8 Application Example of Unused Output Port
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SEP. 2004 Ver 1.03