AT89S52-24AC Atmel, AT89S52-24AC Datasheet - Page 20
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AT89S52-24AC
Manufacturer Part Number
AT89S52-24AC
Description
IC MCU 8K FLASH 24MHZ 44-TQFP
Manufacturer
Atmel
Series
89Sr
Datasheet
1.AT89S52-24AU.pdf
(38 pages)
Specifications of AT89S52-24AC
Core Processor
8051
Core Size
8-Bit
Speed
24MHz
Connectivity
UART/USART
Peripherals
WDT
Number Of I /o
32
Program Memory Size
8KB (8K x 8)
Program Memory Type
FLASH
Ram Size
256 x 8
Voltage - Supply (vcc/vdd)
4 V ~ 5.5 V
Oscillator Type
Internal
Operating Temperature
0°C ~ 70°C
Package / Case
44-TQFP, 44-VQFP
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Eeprom Size
-
Data Converters
-
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17. Program Memory Lock Bits
20
AT89S52
Figure 16-2. External Clock Drive Configuration
Table 16-1.
The AT89S52 has three lock bits that can be left unprogrammed (U) or can be programmed (P)
to obtain the additional features listed in
Table 17-1.
When lock bit 1 is programmed, the logic level at the EA pin is sampled and latched during reset.
If the device is powered up without a reset, the latch initializes to a random value and holds that
value until reset is activated. The latched value of EA must agree with the current logic level at
that pin in order for the device to function properly.
Mode
Idle
Idle
Power-down
Power-down
1
2
3
4
Program Lock Bits
LB1
U
P
P
P
Status of External Pins During Idle and Power-down Modes
Lock Bit Protection Modes
Program
Memory
Internal
External
Internal
External
LB2
U
U
P
P
LB3
U
U
U
P
OSCILLATOR
EXTERNAL
SIGNAL
ALE
NC
1
1
0
0
Protection Type
No program lock features
MOVC instructions executed from external program memory
are disabled from fetching code bytes from internal memory, EA
is sampled and latched on reset, and further programming of
the Flash memory is disabled
Same as mode 2, but verify is also disabled
Same as mode 3, but external execution is also disabled
Table
PSEN
1
1
0
0
17-1.
XTAL2
XTAL1
GND
PORT0
Float
Float
Data
Data
PORT1
Data
Data
Data
Data
Address
PORT2
Data
Data
Data
1919D–MICRO–6/08
PORT3
Data
Data
Data
Data