ATMEGA261 View Datasheet(PDF) - Atmel Corporation
Part Name
Description
MFG CO.
'ATMEGA261' PDF : 226 Pages View PDF
2.2.6
2.2.7
Port B (PB7..PB0)
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 ATtiny261/461/861 as listed
on page 63.
RESET
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 Table 23-3 on page
190. Shorter pulses are not guaranteed to generate a reset.
6 ATtiny261/ATtiny461/ATtiny861
7753E–AVR–06/10
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