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

AC Characteristics - Commercial & Industrial

AC Characteristics - External Bus Cycles

Definition of Symbols

Table 38. External Bus Cycles Timing Symbol Definitions

Signals

A

Address

H

D

Data In

L

L

ALE

V

Q

Data Out

X

R

RD#/PSEN#

Z

W

WR#

Conditions

High

Low

Valid

No Longer Valid

Floating

Timings

Test conditions: capacitive load on all pins = 50 pF.

Table 39 and Table 40 list the AC timing parameters for the TSC80251G2D derivatives

with no wait states. External wait states can be added by extending PSEN#/RD#/WR#

and or by extending ALE. In these tables, Note 2 marks parameters affected by one ALE

wait state, and Note 3 marks parameters affected by PSEN#/RD#/WR# wait states.

Figure 8 to Figure 13 show the bus cycles with the timing parameters.

45

4135F–8051–11/06

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