Rainbow Electronics AT90S2313 - Manual (Page 3)

3
AT90S2313
0839I–AVR–06/02
selectable power-saving modes. The Idle mode stops the CPU while allowing the
SRAM, Timer/Counters, SPI port and interrupt system to continue functioning. The
Power-down mode saves the register contents but freezes the Oscillator, disabling all
other chip functions until the next external interrupt or Hardware Reset.
The device is manufactured using Atmel’s high-density non-volatile memory technology.
The On-chip In-System Programmable Flash allows the Program memory to be repro-
grammed in-system through an SPI serial interface or by a conventional non-volatile
memory programmer. By combining an enhanced RISC 8-bit CPU with In-System Pro-
g ram m abl e F la sh on a mo nol ithi c chi p, th e Atme l AT 90S2 313 is a p ower fu l
microcontroller that provides a highly flexible and cost-effective solution to many embed-
ded control applications.
The AT90S2313 AVR is supported with a full suite of program and system development
tools including: C compilers, macro assemblers, program debugger/simulators, In-Cir-
cuit Emulators and evaluation kits.
Pin Descriptions
VCC Supply voltage pin.
GND Ground pin.
Port B (PB7..PB0) Port B is an 8-bit bi-directional I/O port. Port pins can provide internal pull-up resistors
(selected for each bit). PB0 and PB1 also serve as the positive input (AIN0) and the
negative input (AIN1), respectively, of the On-chip Analog Comparator. The Port B out-
put buffers can sink 20 mA and can drive LED displays directly. When pins PB0 to PB7
are used as inputs and are externally pulled low, they will source current if the internal
pull-up resistors are activated. The Port B pins are tri-stated when a reset condition
becomes active, even if the clock is not active.
Port B also serves the functions of various special features of the AT90S2313 as listed
on page 51.
Port D (PD6..PD0) Port D has seven bi-directional I/O ports with internal pull-up resistors, PD6..PD0. The
Port D output buffers can sink 20 mA. As inputs, Port D pins that are externally pulled
low will source current if the pull-up resistors are activated. The Port D pins are tri-stated
when a reset condition becomes active, even if the clock is not active.
Port D also serves the functions of various special features of the AT90S2313 as listed
on page 56.
RESET Reset input. A low level on this pin for more than 50 ns will generate a Reset, even if the
clock is not running. 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.