TS83C51RB2-VCKB View Datasheet(PDF) - Atmel Corporation
Part Name
Description
Manufacturer
TS83C51RB2-VCKB Datasheet PDF : 74 Pages
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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.
Table 27. AUXR Register
AUXR - Auxiliary Register (8Eh)
7
6
5
4
3
2
1
0
-
-
-
-
-
-
EXTRAM
AO
Bit Number
Bit
Mnemonic
Description
7
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
6
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
5
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
3
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
2
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
1
EXTRAM
EXTRAM bit
See Table 5.
ALE Output bit
0
AO
Clear to restore ALE operation during internal fetches.
Set to disable ALE operation during internal fetches.
Reset Value = XXXX XX00b
Not bit addressable
50
Rev. C - 06 March, 2001
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