Features
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Compatible with MCS
®
-51 Products
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2K Bytes of Reprogrammable Flash Memory
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– Endurance: 1,000 Write/Erase Cycles
2.7V to 6V Operating Range
Fully Static Operation: 0 Hz to 16 MHz
Two-level Program Memory Lock
128 x 8-bit Internal RAM
15 Programmable I/O Lines
Two 16-bit Timer/Counters
Six Interrupt Sources
Programmable Serial UART Channel
Direct LED Drive Outputs
On-chip Analog Comparator
Low-power Idle and Power-down Modes
6 Clocks per Machine Cycle Operation
Description
The AT89C2051x2 is a low-voltage, high-performance CMOS 8-bit microcontroller
with 2K bytes of Flash programmable memory. The device is manufactured using
Atmel’s high-density nonvolatile memory technology and is compatible with the indus-
try-standard MCS-51 instruction set. By combining a versatile 8-bit CPU with Flash on
a monolithic chip, the Atmel AT89C2051x2 is a powerful microcomputer which pro-
vides a highly-flexible and cost-effective solution to many embedded control
applications.
The AT89C2051x2 provides the following standard features: 2K bytes of Flash, 128
bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five-vector, two-level interrupt
architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator
and clock circuitry. In addition, the AT89C2051x2 is designed with static logic for oper-
ation down to zero frequency and supports two software selectable power saving
modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial
port and interrupt system to continue functioning. The power-down mode saves the
RAM contents but freezes the oscillator disabling all other chip functions until the next
hardware reset.
Furthermore, the AT89C2051x2 executes one machine cycle in 6 clock cycles, provid-
ing twice the speed of the AT89C2051 device. The user gains the flexibility to divide
input frequency crystals by 2 (using less expensive components), while keeping the
same CPU power. Alternatively, the user can save on power consumption while keep-
ing the same CPU power (oscillator power saving).
8-bit
Microcontroller
with 2K Bytes
Flash
AT89C2051x2
Pin Configuration
PDIP/SOIC
RST/VPP
(RXD) P3.0
(TXD) P3.1
XTAL2
XTAL1
(INT0) P3.2
(INT1) P3.3
(TO) P3.4
(T1) P3.5
GND
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
VCC
P1.7
P1.6
P1.5
P1.4
P1.3
P1.2
P1.1 (AIN1)
P1.0 (AIN0)
P3.7
Rev. 3285B–MICRO–10/03
1
ATMEL [ ATMEL CORPORATION ]
