on October 28th 10,893

AT89C2051-24PU Microcontroller Guide: Circuit Diagram, Pinout Details, and Datasheet Insights

The AT89C2051-24PU microcontroller by Microchip Technology, a versatile 8-bit CMOS device in a 20-pin DIP package, brings efficiency and low-voltage operation to embedded systems. Known for its compact design and power-saving capabilities, this microcontroller is ideal for battery-powered applications that require reliability and extended device life. In this article, we explore its features, including a comprehensive instruction set, dual power-saving modes, and integrated analog capabilities, highlighting its practical impact across various technological applications. From home automation to low-energy embedded systems, the AT89C2051-24PU exemplifies the balance between performance and compactness.

Catalog

Overview of the AT89C2051-24PU

The AT89C2051-24PU is designed for the exact demands of low-voltage applications. This modestly sized 8-bit microcontroller boasts a high-density nonvolatile memory framework and draws its strength from the MCS-51 instruction set. This combination provides a reliable and efficient performance. By weaving together a versatile CPU and flash memory, it forms an economical and adaptable solution for a range of applications.

The basic components of the AT89C2051-24PU include an analog comparator, oscillators, and clock circuits. These are supported by energy-efficient features like low-power idle modes. This assembly allows for intricate operation with minimal energy consumption

• Idle Mode: This mode disables the CPU but keeps other major components active. It proves beneficial in scenarios demanding extended standby without data loss.

• Power-down Mode: Halts the oscillator while ensuring RAM data is preserved until a hardware reset is performed. This strategy is required for conserving power, especially in battery-operated devices.

The microcontroller accommodates 2K bytes of Flash memory and 128 bytes of RAM. This supports applications needing modest memory capacity. In addition, with 15 I/O lines, it enables extensive peripheral connections, thus enhancing its utility in diverse settings. The AT89C2051-24PU's capabilities are further extended with Dual 16-bit timers/counters for precise timing tasks. A built-in analog comparator for executing complex functions and managing analog signal processing on the chip. These features make it an excellent choice for intricate applications requiring precision and efficiency.

Pin Configuration

Pin Number	Pin Name	Description
20	VCC	Supply voltage.
10	GND	Ground.
19-Dec	Port 1	The Port 1 is an 8-bit bi-directional I/O port. Port pins P1.2 to P1.7 provide internal pull-ups. P1.0 and P1.1 require external pull-ups. P1.0 and P1.1 also serve as the positive input (AIN0) and the negative input (AIN1), respectively, of the on-chip precision analog comparator. The Port 1 output buffers can sink 20 mA and can drive LED displays directly. When 1s are written to Port 1 pins, they can be used as inputs. When pins P1.2 to P1.7 are used as inputs and are externally pulled low, they will source current (IIL) because of the internal pull-ups. Port 1 also receives code data during Flash programming and verification.
2, 3, 6-9, 11	Port 3	Port 3 pins P3.0 to P3.5, P3.7 are seven bi-directional I/O pins with internal pull-ups. P3.6 is hard-wired as an input to the output of the on-chip comparator and is not accessible as a general-purpose I/O pin. The Port 3 output buffers can sink 20 mA. When 1s are written to Port 3 pins are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (IIL) because of the pull-ups. Port 3 also serves the functions of various special features of the AT89C2051 as listed below:
		Port Pin - Alternate Functions
		P3.0 - RXD (serial input port)
		P3.1 - TXD (serial output port)
		P3.2 - INT0 (external interrupt 0)
		P3.3 - INT1 (external interrupt 1)
		P3.4 - T0 (timer 0 external input)
		P3.5 - T1 (timer 1 external input)
		Port 3 also receives some control signals for Flash programming and verification.
1	RST	Reset input. All I/O pins are reset to 1s as soon as RST goes high. Holding the RST pin high for two machine cycles, while the oscillator is running, resets the device. Each machine cycle takes 12 oscillator or clock cycles.
5	XTAL1	Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
4	XTAL2	Output from the inverting oscillator amplifier.

AT89C2051-24PU CAD Specifications

Circuit Diagram Design

PCB Layout Details

3D Visualization

Features

Feature	Description
MCS®-51 Compatibility	Compatible with MCS®-51 Products
Flash Memory	2K Bytes of Reprogrammable Flash Memory
Memory Endurance	10,000 Write/Erase Cycles
Operating Voltage	2.7V to 6V
Operating Frequency	Fully Static Operation: 0 Hz to 24 MHz
Program Memory Lock	Two-level Program Memory Lock
Internal RAM	128 x 8-bit Internal RAM
I/O Lines	15 Programmable I/O Lines
Timer/Counters	Two 16-bit Timer/Counters
Interrupt Sources	Six Interrupt Sources
Serial Communication	Programmable Serial UART Channel
Direct LED Drive Outputs	Available
Analog Comparator	On-chip Analog Comparator
Low-power Modes	Idle and Power-down Modes
Environmental Compliance	Green (Pb/Halide-free) Packaging Option

Technical Specifications

Type	Parameter
Factory Lead Time	10 Weeks
Mount	Through Hole
Mounting Type	Through Hole
Package / Case	20-DIP (0.300, 7.62mm)
Number of Pins	20
Number of I/Os	15
Operating Temperature	-40°C ~ 85°C TA
Packaging	Tube
Series	89C
Published	1995
JESD-609 Code	e3
Pbfree Code	Yes
Part Status	Active
Moisture Sensitivity Level (MSL)	1 (Unlimited)
Number of Terminations	20
Terminal Position	DUAL
Supply Voltage	5V
Frequency	24MHz
Base Part Number	AT89C2051
Operating Supply Voltage	5V
Supply Voltage-Max (Vsup)	6V
Power Supplies	5V
Interface	UART, USART
Memory Size	2kB
Oscillator Type	Internal
RAM Size	128 x 8
Voltage - Supply (Vcc/Vdd)	4V ~ 6V
uPs/uCs/Peripheral ICs Type	Microcontroller
Core Processor	8051
Peripherals	LED
Program Memory Type	FLASH
Core Size	8-Bit
Program Memory Size	2KB (2K x 8)
Connectivity	UART/USART
Bit Size	8
Access Time	24 μs
Has ADC	No
DMA Channels	No
Data Bus Width	8b
PWM Channels	No
DAC Channels	No
Number of Timers/Counters	2
Address Bus Width	8b
Number of UART Channels	1
Height	4.963mm
Length	26.92mm
Width	7.112mm
REACH SVHC	No SVHC
Radiation Hardening	No
RoHS Status	RoHS3 Compliant
Lead Free	Lead Free

Parts with Similar Specs

Part Number	Manufacturer	Package / Case	Number of Pins	Data Bus Width	Number of I/O	Interface	Memory Size	Supply Voltage	Peripherals	View Compare
AT89C2051-24PU	Microchip Technology	20-DIP (0.300, 7.62mm)	20	8 b	15	UART, USART	2 kB	5 V	LED	AT89C2051-24PU VS AT89LP2052-20PU
AT89LP2052-20PU	Microchip Technology	20-DIP (0.300, 7.62mm)	-	-	18	-	-	3 V	LVD, POR, PWM, WDT	AT89C2051-24PU VS AT89LP2052-20PU
AT89LP213-20PU	Microchip Technology	14-DIP (0.300, 7.62mm)	14	8 b	12	SPI, UART	2 kB	-	Brown-out Detect/Reset, POR, PWM, WDT	AT89C2051-24PU VS AT89LP213-20PU
AT89LP214-20PU	Microchip Technology	20-DIP (0.300, 7.62mm)	20	8 b	15	SPI, UART, USART	2 kB	3 V	Brown-out Detect/Reset, POR, PWM, WDT	AT89C2051-24PU VS AT89LP214-20PU
MC9RS08KA8CPJ	NXP USA Inc.	14-DIP (0.300, 7.62mm)	14	8 b	12	SPI, UART, USART	2 kB	2.7 V	Brown-out Detect/Reset, POR, PWM, WDT	AT89C2051-24PU VS MC9RS08KA8CP

Functional Block Diagram

Electronic Digital Clock Using AT89C2051

Digital clocks express time through numeric displays, creating a contrast to traditional analog forms. Their presence is notable in homes, offices, and public areas due to their precise timekeeping and ease of reading. This part unveils the process of building a 4-bit digital clock using the AT89C2051.

The AT89C2051, part of the 8051-microcontroller family, is renowned for its efficiency and adaptability. With a 24MHz frequency, diverse I/O lines, timers, and interrupt functions, it caters to various embedded applications. Its implementations often underline its dependability in both straightforward and intricate projects.

AT89C2051-24PU Flash Storage

Flash Memory Programming

Flash Memory Verification

Flash Programming and Verification Waveforms

Exploring Alternatives to AT89C2051-24PU

Part Number	Category	Description	Manufacturer
AT89C2051-24PC	MICROCONTROLLERS AND PROCESSORS	Microcontroller, 8-Bit, FLASH, 8051 CPU, 24MHz, CMOS, PDIP20, 0.300 INCH, PLASTIC, MS-001AD, DIP-20	Atmel Corporation
AT89C2051-24PI	MICROCONTROLLERS AND PROCESSORS	Microcontroller, 8-Bit, FLASH, 8051 CPU, 24MHz, CMOS, PDIP20, 0.300 INCH, PLASTIC, MS-001AD, DIP-20	Atmel Corporation
AT89C2051-24PU	MICROCONTROLLERS AND PROCESSORS	Microcontroller, 8-Bit, FLASH, 8051 CPU, 24MHz, CMOS, PDIP20, 0.300 INCH, GREEN, PLASTIC, MS-001AD, DIP-20	Atmel Corporation

Applications of AT89C2051-24PU

Idle Mode

The AT89C2051-24PU microcontroller introduces Idle Mode as a distinct operational state. Here, while the CPU pauses its activities, basic components like RAM, timers, serial ports, and interrupts continue to function. This balance offers an intriguing solution for applications that require prolonged battery life while maintaining core operations.

Idle Mode's ability to lower power usage dramatically enhances the longevity of portable devices. With considerations for both cost and environmental impact, reducing energy consumption becomes a compelling aspect of design. Integrating this mode allows systems to optimize efficiency, mostly during idle times. Idle Mode finds practical use across various domains.

In automation systems, where sensors constantly gather data, processing is activated only when required. Smart home devices benefit by conserving energy during standby, yet ensure smooth operation. Remote or difficult-to-reach installations, where frequent maintenance isn't practical, greatly benefit from its energy-saving properties.

Package

Symbol	Min (mm)	Nom (mm)	Max (mm)	Note
A	-	-	5.334
A1	0.381	-	-
D	24.892	-	26.924	Note 2
E	7.62	-	8.255
E1	6.096	-	7.112	Note 2
B	0.356	-	0.559
B1	1.27	-	1.651
L	2.921	-	3.81
C	0.203	-	0.356
eB	-	-	10.922
eC	0	-	1.524
e	2.540 TYP

Notes:

This package conforms to JEDEC reference MS-001, Variation AD.

Dimensions D and E1 do not include mold flash or protrusion. Mold flash or protrusion shall not exceed 0.25 mm (0.010").

Manufacturer Insights

Microchip Technology calls Chandler, Arizona home, thriving in the world of microcontrollers and analog semiconductors. This organization is recognized for creating holistic solutions that deftly lower client risks without bloating budgets while setting a high bar for product consistency in the industry.

Technical support forms the backbone of Microchip's offerings. Their comprehensive customer service empowers you during the integration process. This not only strengthens client relationships but also creates a culture of reliability and forward-thinking. Microchip's relentless pursuit of product consistency shines through its rigorous testing and quality assurance protocols. Cutting-edge quality control measures ensure products perform excellently across various applications, enhancing their longevity and dependability.

Datasheet PDF

AT89C2051-24PU Datasheets:

AT89C2051.pdf

AT89LP2052-20PU Datasheets:

Cylindrical Battery Holders.pdf

AT89LP214-20PU Datasheets:

Cylindrical Battery Holders.pdf

Frequently Asked Questions [FAQ]

1. What are the differences between AT89C51 and AT89C2051?

The AT89C2051, with its compact form and straightforward design, offers 2KB ROM and 2 I/O ports. In contrast, the AT89C51 provides 4KB ROM and 4 ports. This makes the AT89C2051 ideal for systems where minimal external RAM suffices, providing a cost-effective solution for projects prioritizing efficiency.

2. How do the programming methods for AT89C2051 compare with AT89S2051?

Programming interfaces vary: the AT-series employs parallel port methods, while AT89S2051 from the STC series utilizes serial communication with the MAX232 interface. This affects your interaction with hardware, influencing decisions based on tool availability and needs.

3. How do AT89C2051 and 89C51 MCUs differ?

The AT89C2051, offering half the memory of the 89C51 and missing the P3.7 pin, provides limited expandability. Constraints often lead to a preference for assembly language, necessitating careful consideration of application needs when selecting the right platform.

4. What is the package type for AT89C2051-24PU?

It is available in a 20-pin Dual In-Line Package (DIP), which simplifies prototyping and small-scale production efforts.

5. Which instruction set does the AT89C2051-24PU support?

The AT89C2051-24PU supports the MCS-51 instruction set. This well-established standard supports a wide range of applications despite the controller's limited size.

6. What type of CPU is in the AT89C2051-24PU?

Equipped with an 8-bit CPU, it balances performance and simplicity, making it suitable for a variety of embedded system tasks.

7. How does the AT89C2051-24PU support low-frequency operations?

Static logic in the AT89C2051-24PU enables efficient low-frequency operations. This is advantageous in applications focused on minimizing power consumption, like battery-operated devices.

8. How is RAM preserved when the oscillator is inactive?

RAM content is maintained through power-down mode when the oscillator shuts off, ensuring data preservation in low-power states. This feature is used where data integrity remains a priority despite energy limitations.

9. What feature does the AT89C2051 offer for low-frequency operations?

With its static logic, the AT89C2051 supports effective low-frequency functionality, thus optimizing power efficiency without compromising performance.

10. When does the CPU stop operating?

In Idle Mode, the CPU halts while peripherals remain active, allowing peripheral functionality to continue as power is conserved.

11. What happens to RAM if the oscillator stops?

RAM remains intact even when the oscillator ceases operation, thus safeguarding data during low-power transitions, which is active for applications demanding reliable data retention.