AT80251G2D-3CSUM(2006) View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT80251G2D-3CSUM
(Rev.:2006)

8/16-bit Microcontroller with Serial Communication Interfaces

Atmel Corporation 

Configuration Byte 1

Table 13. Address Ranges and Usage of RD#, WR# and PSEN# Signals

RD1

RD0

P1.7 P3.7/RD# PSEN#

WR#

External

Memory

Read signal for all Write signal for all

0

0

A17 A16

external memory external memory

256 KB

locations

locations

Read signal for all Write signal for all

0

1

I/O pin A16

external memory external memory

128 KB

locations

locations

Read signal for all Write signal for all

1

0

I/O pin I/O pin

external memory external memory

64 KB

locations

locations

1

1

I/O pin

Read

signal for

regions 00:

and 01:

Read signal for

regions FE: and FF:

Write signal for all

external memory

locations

2 × 64 KB(1)

Notes: 1. This selection provides compatibility with the standard 80C51 hardware which has

separate external memory spaces for data and code.

20 AT/TSC8x251G2D

4135F–8051–11/06

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