Atmel AVR AT90LS4434, Предварительный

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AT90S/LS4434 and AT90S/LS8535
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The AVR core combines a rich instruction set with 32 general-purpose working registers. All the 32 registers are directly
connected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction
executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times
faster than conventional CISC microcontrollers.
The AT90S4434/8535 provides the following features: 4K/8K bytes of In-System Programmable Flash, 256/512 bytes
EEPROM, 256/512 bytes SRAM, 32 general-purpose I/O lines, 32 general-purpose working registers, Real-time Clock
(RTC), three flexible timer/counters with compare modes, internal and external interrupts, a programmable serial UART,
8-channel, 10-bit ADC, programmable Watchdog Timer with internal oscillator, an SPI serial port and three software-
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, dis-
abling all other chip functions until the next interrupt or hardware reset. In Power Save Mode, the timer oscillator continues
to run, allowing the user to maintain a timer base while the rest of the device is sleeping.
The device is manufactured using Atmel’s high-density nonvolatile memory technology. The on-chip ISP Flash allows the
program memory to be reprogrammed in-system through an SPI serial interface or by a conventional nonvolatile memory
programmer. By combining an 8-bit RISC CPU with In-System Programmable Flash on a monolithic chip, the Atmel
AT90S4434/8535 is a powerful microcontroller that provides a highly flexible and cost effective solution to many embedded
control applications.
The AT90S4434/8535 AVR is supported with a full suite of program and system development tools including: C compilers,
macro assemblers, program debugger/simulators, in-circuit emulators and evaluation kits.
Comparison between AT90S4434 and AT90S8535
The AT90S4434 has 4K bytes of In-System Programmable Flash, 256 bytes of EEPROM and 256 bytes of internal SRAM.
The AT90S8535 has 8K bytes of In-System Programmable Flash, 512 bytes of EEPROM and 512 bytes of internal SRAM.
Table 1 summarizes the different memory sizes for the two devices.
Pin Descriptions
VCC
Digital supply voltage
GND
Digital ground
Port A (PA7..PA0)
Port A is an 8-bit bi-directional I/O port. Port pins can provide internal pull-up resistors (selected for each bit). The Port A
output buffers can sink 20 mA and can drive LED displays directly. When pins PA0 to PA7 are used as inputs and are
externally pulled low, they will source current if the internal pull-up resistors are activated.
Port A also serves as the analog inputs to the A/D Converter.
The Port A pins are tri-stated when a reset condition becomes active, even if the clock is not running.
Port B (PB7..PB0)
Port B is an 8-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 of the AT90S4434/8535 as listed on page 71.
Table 1. Memory Size Summary
Part Flash EEPROM SRAM
AT90S4434 4K bytes 256 bytes 256 bytes
AT90S8535 8K bytes 512 bytes 512 bytes