Rainbow Electronics ATtiny43U - Manual (Page 3)

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8048B–AVR–03/09
capability except PA7 which has the RESET capability. To use pin PA7 as an I/O pin, instead of
RESET pin, program (‘0’) RSTDISBL fuse. 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
“Alternate Port Functions” on page 67 .
1.1.4 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 20-4 on page
158 . Shorter pulses are not guaranteed to generate a reset.
1.1.5 Port B (PB7:PB0)
Port B is a 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 as listed in Section 11.3 “Alternate
Port Functions” on page 67 .
1.1.6 LSW
Boost converter external inductor connection. Connect to ground when boost converter is dis-
abled permanently.
1.1.7 V
BAT
Battery supply voltage. Connect to ground when boost converter is disabled permanently.