AT89C51ED2-RDTIM datasheet(95/137 Pages) ATMEL

95 / 137 page

AT89C51RD2/ED2

4235E–8051–04/04

Flash/EEPROM

Memory

The Flash memory increases EEPROM and ROM functionality with in-circuit electrical

erasure and programming. It contains 64K bytes of program memory organized respec-

tively in 512 pages of 128 bytes. This memory is both parallel and serial In-System

Programmable (ISP). ISP allows devices to alter their own program memory in the

actual end product under software control. A default serial loader (bootloader) program

allows ISP of the Flash.

The programming does not require external dedicated programming voltage. The nec-

essary high programming voltage is generated on-chip using the standard VCC pins of

the microcontroller.

Features

•

Flash EEPROM Internal Program Memory

•

Boot vector allows user provided Flash loader code to reside anywhere in the Flash

memory space. This configuration provides flexibility to the user.

•

Default loader in Boot ROM allows programming via the serial port without the need

of a user provided loader.

•

Up to 64K bytes external program memory if the internal program memory is

disabled (EA = 0).

•

Programming and erasing voltage with standard power supply

•

Read/Programming/Erase:

–

Byte-wise read without wait state

–

Byte or page erase and programming (10 ms)

•

Typical programming time (64K bytes) is 22s with on chip serial bootloader

•

Parallel programming with 87C51 compatible hardware interface to programmer

•

Programmable security for the code in the Flash

•

100K write cycles

•

10 years data retention

Flash Programming and

Erasure

The 64-K byte Flash is programmed by bytes or by pages of 128 bytes. It is not neces-

sary to erase a byte or a page before programming. The programming of a byte or a

page includes a self erase before programming.

There are three methods of programming the Flash memory:

The on-chip ISP bootloader may be invoked which will use low level routines to

program the pages. The interface used for serial downloading of Flash is the

UART.

The Flash may be programmed or erased in the end-user application by calling

low-level routines through a common entry point in the Boot ROM.

The Flash may be programmed using the parallel method by using a conven-

tional EPROM programmer. The parallel programming method used by these

devices is similar to that used by EPROM 87C51 but it is not identical and the

commercially available programmers need to have support for the

AT89C51RD2/ED2. The bootloader and the Application Programming Interface

(API) routines are located in the BOOT ROM.

AT89C51ED2-RDTIM 数据表(PDF) 95 Page - ATMEL Corporation

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