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Comparison between
AT90S/LS2323 and
AT90S/LS2343
Pin Descriptions
AT90S/LS2323
VCC
GND
Port B (PB2..PB0)
RESET
XTAL1
XTAL2
AT90S/LS2323/2343
4
chip, the Atmel AT90S2323/2343 is a powerful microcontroller that provides a highly
flexible and cost-effective solution to many embedded control applications.
The AT90S2323/2343 AVR is supported with a full suite of program and system devel-
opment tools including: C compilers, macro assemblers, program debugger/simulators,
in-circuit emulators and evaluation kits.
The AT90S/LS2323 is intended for use with external quartz crystal or ceramic resonator
as the clock source. The start-up time is fuse-selectable as either 1 ms (suitable for
ceramic resonator) or 16 ms (suitable for crystal). The device has three I/O pins.
The AT90S/LS2343 is intended for use with either an external clock source or the inter-
nal RC oscillator as clock source. The device has five I/O pins.
Table 1 summarizes the differences in features of the two devices.
Table 1. Feature Difference Summary
Part
On-chip Oscillator Amplifier
Internal RC Clock
PB3 available as I/O pin
PB4 available as I/O pin
Start-up time
Supply voltage pin.
Ground pin.
Port B is a 3-bit bi-directional I/O port with internal pull-up resistors. The Port B output
buffers can sink 20 mA. As inputs, Port B pins that are externally pulled low, will source
current if the pull-up resistors are activated.
Port B also serves the functions of various special features.
Port pins can provide internal pull-up resistors (selected for each bit). The Port B pins
are tri-stated when a reset condition becomes active.
Reset input. An external reset is generated by a low level on the RESET pin. Reset
pulses longer than 50 ns will generate a reset, even if the clock is not running. Shorter
pulses are not guaranteed to generate a reset.
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
Output from the inverting oscillator amplifier.
AT90S/LS2323
AT90S/LS2343
yes
no
no
yes
never
internal clock mode
never
always
1 ms/16 ms
16 µs fixed
1004D–09/01
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