Rainbow Electronics AT90LS2343 - Manual (Page 3)

3
AT90S/LS2323/2343
1004D–09/01
Figure 2. The AT90S/LS2323 Block Diagram
The AT90S2323/2343 provides the following features: 2K bytes of In-System Program-
m a bl e F la s h , 1 2 8 b y t es E E P R O M , 12 8 b y t e s S R A M , 3 ( A T9 0 S /L S 2 3 2 3 ) / 5
(AT90S/LS2343) general-purpose I/O lines, 32 general-purpose working registers, an 8-
bit timer/counter, internal and external interrupts, programmable Watchdog Timer with
internal oscillator, an SPI serial port for Flash Memory downloading and two 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, disabling all
other chip functions until the next interrupt or hardware reset.
The device is manufactured using Atmel’s high-density nonvolatile memory technology.
The On-chip Flash allows the program memory to be reprogrammed in-system through
an SPI serial interface. By combining an 8-bit RISC CPU with ISP Flash on a monolithic
PROGRAM
COUNTER
INTERNAL
OSCILLATOR
WATCHDOG
TIMER
STACK
POINTER
PROGRAM
FLASH
MCU CONTROL
REGISTER
SRAM
GENERAL
PURPOSE
REGISTERS
INSTRUCTION
REGISTER
TIMER/
COUNTER
INSTRUCTION
DECODER
DATA DIR.
REG. PORTB
DATA REGISTER
PORTB
PROGRAMMING
LOGIC
TIMING AND
CONTROL
OSCILLATOR
INTERRUPT
UNIT
EEPROM
SPI
STATUS
REGISTER
Z
Y
X
ALU
PORTB DRIVERS
PB0 - PB2
RESET
VCC
GND
CONTROL
LINES
8-BIT DATA BUS