TS87C51RC2 ATMEL Corporation, TS87C51RC2 Datasheet - Page 17

• Manufacturer Part Number: TS87C51RC2
• Description: High Performance 8-bit Microcontroller 32 Kbytes Otp
• Manufacturer: ATMEL Corporation

Rev. C - 06 March, 2001
FF(RA, RB, RC)/2FF (RD)
00
Address 08EH
256 bytes
a.
XRAM
AUXR
EXTRAM
Symbol
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.
Figure 4. Internal and External Data Memory Address
AO
-
Reset value
Table 5. Auxiliary Register
Not implemented, reserved for future use.
Disable/Enable ALE
Internal/External RAM (00H-FFH) access using MOVX @ Ri/ @ DPTR
FF
EXTRAM
80
00
AO
0
1
0
1
indirect accesses
direct or indirect
128 bytes
128 bytes
accesses
Internal
Internal
X
Lower
Upper
-
Ram
Ram
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
Operating Mode
Internal XRAM access using MOVX @ Ri/ @ DPTR
External data memory access
X
-
FF
80
X
-
0100 (RA, RB, RC) or 0300 (RD)
AUXR
direct accesses
Function
a
Function
Register
Special
X
TS83C51RB2/RC2/RD2
TS87C51RB2/RC2/RD2
-
X
-
TS80C51RA2/RD2
FFFF
0000
X
-
EXTRA
M
Memory
External
0
Data
AO
0
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