TS87C51RC2 ATMEL Corporation, TS87C51RC2 Datasheet - Page 50

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

TS80C51RA2/RD2
TS83C51RB2/RC2/RD2
TS87C51RB2/RC2/RD2
6.13. Reduced EMI Mode
The ALE signal is used to demultiplex address and data buses on port 0 when used with external program or data
memory. Nevertheless, during internal code execution, ALE signal is still generated. In order to reduce EMI, ALE
signal can be disabled by setting AO bit.
The AO bit is located in AUXR register at bit location 0. As soon as AO is set, ALE is no longer output but
remains active during MOVX and MOVC instructions and external fetches. During ALE disabling, ALE pin is
weakly pulled high.
AUXR - Auxiliary Register (8Eh)
Reset Value = XXXX XX00b
Not bit addressable
50
Bit Number
7
6
5
4
3
2
1
0
7
-
Mnemonic
EXTRAM
Bit
AO
-
-
-
-
-
-
6
-
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
EXTRAM bit
ALE Output bit
The value read from this bit is indeterminate. Do not set this bit.
The value read from this bit is indeterminate. Do not set this bit.
The value read from this bit is indeterminate. Do not set this bit.
The value read from this bit is indeterminate. Do not set this bit.
The value read from this bit is indeterminate. Do not set this bit.
The value read from this bit is indeterminate. Do not set this bit.
See Table 5.
Clear to restore ALE operation during internal fetches.
Set to disable ALE operation during internal fetches.
5
-
Table 27. AUXR Register
4
-
3
-
Description
2
-
EXTRAM
Rev. C - 06 March, 2001
1
AO
0