atmega32c1 ATMEL Corporation, atmega32c1 Datasheet - Page 10

• Manufacturer Part Number: atmega32c1
• Description: Atmega32m1 Automotive 8-bit Avr Microcontroller With 32k/64k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

2.3.3
2.3.4
2.3.5
2.3.6
10
ATmega32/64/M1/C1
Port B (PB7..PB0)
Port C (PC7..PC0)
Port D (PD7..PD0)
Port E (PE2..0) RESET/ XTAL1/
XTAL2
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 also serves the functions of various special features of the ATmega32/64/M1/C1 as listed
on
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 ATmega32/64/M1/C1 as listed on
page
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.
Port D also serves the functions of various special features of the ATmega32/64/M1/C1 as listed
on
Port E is an 3-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port E output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port E pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port E pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
If the RSTDISBL Fuse is programmed, PE0 is used as an I/O pin. Note that the electrical char-
acteristics of PE0 differ from those of the other pins of Port E.
If the RSTDISBL Fuse is unprogrammed, PE0 is used as a Reset input. A low level on this pin
for longer than the minimum pulse length will generate a Reset, even if the clock is not running.
The minimum pulse length is given in
to generate a Reset.
Depending on the clock selection fuse settings, PE1 can be used as input to the inverting Oscil-
lator amplifier and input to the internal clock operating circuit.
Depending on the clock selection fuse settings, PE2 can be used as output from the inverting
Oscillator amplifier.
page
page
71.
67.
74.
Table 7-1 on page
45. Shorter pulses are not guaranteed
7647A–AVR–02/08