ATA5771_09 ATMEL [ATMEL Corporation], ATA5771_09 Datasheet - Page 58

• Manufacturer Part Number: ATA5771_09
• Description: Microcontroller with UHF ASK/FSK Transmitter
• Manufacturer: ATMEL [ATMEL Corporation]

2.3
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
7701C–AVR–12/08
Pin Descriptions
VCC
GND
Port B (PB3...PB0)
RESET
Port A (PA7...PA0)
Supply voltage.
Ground.
Port B is a 4-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 except PB3 which has the RESET capability. To use pin PB3 as an I/O pin, instead of
RESET pin, program (‘0’) RSTDISBL fuse. 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 ATtiny24/44/84 as listed on
Section 12.3 ”Alternate Port Functions” on page
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
41. Shorter pulses are not guaranteed to generate a reset.
Port A is a 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 has an alternate functions as analog inputs for the ADC, analog comparator, timer/coun-
ter, SPI and pin change interrupt as described in
61.
”Alternate Port Functions” on page 61
ATtiny24/44/84
Table 9-1 on page
5