AT89C51ED2-RDTUM datasheet(97/137 Pages) ATMEL

97 / 137 page

4235K–8051–05/08

AT89C51RD2/ED2

Table 24-5.

User Memory Lock Bits of the SSB

Note:

X: Do not care

WARNING: Security level 2 and 3 should only be programmed after Flash verification.

24.4

Flash Memory Status

AT89C51RD2/ED2 parts are delivered in standard with the ISP ROM bootloader.

After ISP or parallel programming, the possible contents of the Flash memory are summarized in

Figure 24-1:

Figure 24-1. Flash Memory Possible Contents

24.5

Memory Organization

When the EA pin is high, the processor fetches instructions from internal program Flash. If the

EA pin is tied low, all program memory fetches are from external memory.

24.6

Bootloader Architecture

24.6.1

Introduction

The bootloader manages communication according to a specifically defined protocol to provide

the whole access and service on Flash memory. Furthermore, all accesses and routines can be

called from the user application.

Program Lock Bits

Protection Description

Security

Level

LB0

LB1

No program lock features enabled.

ISP programming of the Flash is disabled.

Same as 2, also verify through ISP programming interface is disabled.

0000h

Virgin

Default

After ISP

After Parallel

Programming

After Parallel

Programming

After Parallel

Programming

Application

Virgin

After ISP

Dedicated

ISP

Dedicated

ISP

Application

Virgin

Application

Virgin

Application

FFFFh

AT89C51ED2-RDTUM bảng dữ liệu(PDF) 97 Page - ATMEL Corporation

AT89C51ED2-RDTUM bảng dữ liệu(HTML) 97 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

bảng dữ liệu tải về

Link URL