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 

AT/TSC8x251G2D

Waveforms in Page Mode

Figure 10. External Bus Cycle: Data Write (Non-Page Mode)

ALE

TLHLL(1)

TWLWH(1)

TWHLH

WR#

TLHAX(1)

TAVLL(1) TLLAX

TQVWH

TWHQX

P0

A7:0

TAVWL1(1)

TAVWL2(1)

D7:0

Data Out

TWHAX

P2/A16/A17

A15:8/A16/A17

Note: 1. The value of this parameter depends on wait states. See Table 39 and Table 40.

Figure 11. External Bus Cycle: Code Fetch (Page Mode)

ALE

TLHLL(1)

TLLRL(1)

PSEN#(3)

P2

P0/A16/A17

TRLAZ

TLHAX(1)

TAVLL(1) TLLAX

TRLDV(1)

TRHDZ1

TRHDX

A15:8

TAVRL(1)

TAVDV1(1)

TAVDV2(1)

D7:0

Instruction In

D7:0

Instruction In

TAXDX

TAVDV3(1)

TRHAX

A7:0/A16/A17

Page Miss(2)

A7:0/A16/A17

Page Hit(2)

Note:

1. The value of this parameter depends on wait states. See Table 39 and Table 40.

2. A page hit (i.e., a code fetch to the same 256-byte “page” as the previous code fetch)

requires one state (2·TOSC);

a page miss requires two states (4·TOSC).

3. During a sequence of page hits, PSEN# remains low until the end of the last page-hit

cycle.

49

4135F–8051–11/06

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