atmega169a-mch ATMEL Corporation, atmega169a-mch Datasheet - Page 8

• Manufacturer Part Number: atmega169a-mch
• Description: 8-bit Avr 8-bit Microcontroller Microcontroller With 32k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

2.3
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
2.3.6
8
Pin Descriptions
ATmega169A/169PA/329A/329PA/649A/649P/3290A/3290PA/6490A/6490P
V
GND
Port A (PA7...PA0)
Port B (PB7...PB0)
Port C (PC7...PC0)
Port D (PD7...PD0)
CC
The following section describes the I/O-pin special functions.
Digital supply voltage.
Ground.
Port A is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port A output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port A pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port A pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
Port A also serves the functions of various special features of the
ATmega169A/169PA/329A/329PA/3290A/3290PA/649A/649P/6490A/6490P as listed on
74.
Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port B output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port B pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port B pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
Port B has better driving capabilities than the other ports.
P o r t B a l s o s e r v e s t h e f u n c t i o n s o f v a r i o u s s p e c i a l f e a t u r e s o f t h e
ATmega169A/169PA/329A/329PA/3290A/3290PA/649A/649P/6490A/6490P as listed on
75.
Port C is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port C output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port C pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port C pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
Port C also serves the functions of special features of the
ATmega169A/169PA/329A/329PA/3290A/3290PA/649A/649P/6490A/6490P as listed on
78.
Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port D output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port D pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port D pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
8284AS–AVR–10/10
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