TS87C54X2 Temic Semiconductors, TS87C54X2 Datasheet - Page 34

• Manufacturer Part Number: TS87C54X2
• Description: 8-bit CMOS Microcontroller 0-60 MHz
• Manufacturer: Temic Semiconductors

TS80C54X2/C58X2
TS87C54X2/C58X2
6.11 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
34
Number
Bit
7
6
5
4
3
2
1
0
7
-
Mnemonic
RESERVED
Bit
AO
-
-
-
-
-
-
6
-
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
This bit must be set for normal operation
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.
For ALE disabling, program 03H in AUXR register.
For standard operation, program 02H in AUXR register.
Clear to restore ALE operation during internal fetches.
Set to disable ALE operation during internal fetches.
5
-
Table 19. AUXR Register
4
-
3
-
Description
2
-
RESERVED
Rev. B - Aug. 31, 1999
1
AO
0