1
0401F–MICRO–11/03
Features
Compatible with MCS
®
51

Products
8K Bytes of In-System Reprogrammable Downloadable Flash Memory
– SPI Serial Interface for Program Downloading
– Endurance: 1,000 Write/Erase Cycles
2K Bytes EEPROM
– Endurance: 100,000 Write/Erase Cycles
4V to 6V Operating Range
Fully Static Operation: 0 Hz to 24 MHz
Three-level Program Memory Lock
256 x 8-bit Internal RAM
32 Programmable I/O Lines
Three 16-bit Timer/Counters
Nine Interrupt Sources
Programmable UART Serial Channel
SPI Serial Interface
Low-power Idle and Power-down Modes
Interrupt Recovery from Power-down
Programmable Watchdog Timer
Dual Data Pointer
Power-off Flag
Description
The AT89S8252 is a low-power, high-performance CMOS 8-bit microcontroller with 8K
bytes of downloadable Flash programmable and erasable read-only memory and 2K
bytes of EEPROM. The device is manufactured using Atmel’s high-density nonvolatile
memory technology and is compatible with the industry-standard 80C51 instruction
set and pinout. The on-chip downloadable Flash allows the program memory to be
reprogrammed In-System through an SPI serial interface or by a conventional nonvol-
atile memory programmer. By combining a versatile 8-bit CPU with downloadable
Flash on a monolithic chip, the Atmel AT89S8252 is a powerful microcontroller, which
provides a highly-flexible and cost-effective solution to many embedded control
applications.
The AT89S8252 provides the following standard features: 8K bytes of downloadable
Flash, 2K bytes of EEPROM, 256 bytes of RAM, 32 I/O lines, programmable watchdog
timer, two data pointers, three 16-bit timer/counters, a six-vector two-level interrupt
architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition,
the AT89S8252 is designed with static logic for operation down to zero frequency and
supports two software selectable power saving modes. The Idle Mode stops the CPU
while allowing the RAM, timer/counters, serial port, and interrupt system to continue
functioning. The Power-down mode saves the RAM contents but freezes the oscillator,
disabling all other chip functions until the next external interrupt or hardware reset.
The downloadable Flash can be changed a single byte at a time and is accessible
through the SPI serial interface. Holding RESET active forces the SPI bus into a serial
programming interface and allows the program memory to be written to or read from
unless lock bits have been activated.
8-bit
Microcontroller
with 8K Bytes
Flash
AT89S8252