Rainbow Electronics Atmega169L - Manual (Page 6)

6
ATmega169V/L
2514A–AVR–08/02
resistors are activated. The Port F pins are tri-stated when a reset condition becomes
active, even if the clock is not running. If the JTAG interface is enabled, the pull-up resis-
tors on pins PF7(TDI), PF5(TMS), and PF4(TCK) will be activated even if a reset
occurs.
Port F also serves the functions of the JTAG interface.
Port G (PG5..PG0) Port G is a 6-bit I/O port with internal pull-up resistors (selected for each bit). PG5 is
input only, the rest of the pins are bi-directional. The Port G output buffers have symmet-
rical drive characteristics with both high sink and source capability. As inputs, Port G
pins that are externally pulled low will source current if the pull-up resistors are acti-
vated. The Port G pins are tri-stated when a reset condition becomes active, even if the
clock is not running.
Port G also serves the functions of various special features of the ATmega169 as listed
on page 65.
RESET Reset input. A low level on this pin for longer than the minimum pulse length will gener-
ate a reset, even if the clock is not running. The minimum pulse length is given in Table
16 on page 37. Shorter pulses are not guaranteed to generate a reset.
XTAL1 Input to the inverting Oscillator amplifier and input to the internal clock operating circuit.
XTAL2 Output from the inverting Oscillator amplifier.
AVCC AVCC is the supply voltage pin for Port A and the A/D Converter. It should be externally
connected to V
CC
, even if the ADC is not used. If the ADC is used, it should be con-
nected to V
CC
through a low-pass filter.
AREF This is the analog reference pin for the A/D Converter.
About Code
Examples
This documentation contains simple code examples that briefly show how to use various
parts of the device. These code examples assume that the part specific header file is
included before compilation. Be aware that not all C compiler vendors include bit defini-
tions in the header files and interrupt handling in C is compiler dependent. Please
confirm with the C compiler documentation for more details.