AT87C52X2-RLTUM Atmel, AT87C52X2-RLTUM Datasheet - Page 30

• Manufacturer Part Number: AT87C52X2-RLTUM
• Description: IC 8051 MCU 8K OTP 40MHZ 44VQFP
• Manufacturer: Atmel
• Series: 87Cr

Specifications of AT87C52X2-RLTUM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40/20MHz
• Connectivity: UART/USART
• Peripherals: POR
• Number Of I /o: 32
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: OTP
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -

Reduced EMI Mode
30
TS8xCx2X2
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 18. AUXR Register
AUXR - Auxiliary Register (8Eh)
Reset Value = XXXX XXX0b
Not bit addressable
Number
Bit
7
-
7
6
5
4
3
2
1
0
Mnemonic Description
Bit
AO
6
-
-
-
-
-
-
-
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
ALE Output bit
Clear to restore ALE operation during internal fetches.
Set to disable ALE operation during internal fetches.
5
-
4
-
3
-
2
-
1
-
4184G–8051–09/06
AO
0