TS80C51RA2-VCKB datasheet(17/74 Pages) ATMEL

17 / 74 page

Rev. C - 06 March, 2001

TS80C51RA2/RD2

TS83C51RB2/RC2/RD2

TS87C51RB2/RC2/RD2

Figure 4. Internal and External Data Memory Address

Table 5. Auxiliary Register

AUXR

Address 08EH

EXTRA

Reset value

Symbol

Function

Not implemented, reserved for future use.a

User software should not write 1s to reserved bits. These bits may be used in future 8051 family

products to invoke new features. In that case, the reset or inactive value of the new bit will be 0, and

its active value will be 1. The value read from a reserved bit is indeterminate.

Disable/Enable ALE

Operating Mode

ALE is emitted at a constant rate of 1/6 the oscillator frequency (or 1/3 if

X2 mode is used)

ALE is active only during a MOVX or MOVC instruction

EXTRAM

Internal/External RAM (00H-FFH) access using MOVX @ Ri/ @ DPTR

EXTRAM

Operating Mode

Internal XRAM access using MOVX @ Ri/ @ DPTR

External data memory access

XRAM

256 bytes

Upper

128 bytes

Internal

Ram

Lower

128 bytes

Internal

Ram

Special

Function

FF(RA, RB, RC)/2FF (RD)

External

Data

Memory

0000

0100 (RA, RB, RC) or 0300 (RD)

FFFF

indirect accesses

direct accesses

direct or indirect

accesses

TS80C51RA2-VCKB Datasheet(PDF) 17 Page - ATMEL Corporation

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