1. Introducció
This manual provides essential information for the proper use, setup, and maintenance of the MICROCHIP TECHNOLOGY ATmega8-16PU microcontroller. The ATmega8-16PU is a low-power, 8-bit CMOS microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega8-16PU achieves throughputs approaching 1 MIPS per MHz, allowing the system designer to optimize power consumption versus processing speed.
2. Producte acabatview
The ATmega8-16PU is a versatile 8-bit microcontroller designed for a wide range of embedded applications. It features 8KB of In-System Self-Programmable Flash memory, 512 bytes of EEPROM, 1KB of SRAM, 23 general purpose I/O lines, 32 general purpose working registers, three flexible Timer/Counters with compare modes, internal and external interrupts, a serial programmable USART, a byte oriented Two-wire Serial Interface, a 6-channel ADC (8-channel in TQFP and QFN/MLF packages), a programmable Watchdog Timer with internal Oscillator, an SPI serial port, and six software selectable power saving modes. The device operates between 4.5-5.5 volts and is available in a 28-pin PDIP package.
Figure 1: The ATmega8-16PU microcontroller in a 28-pin PDIP package. This image displays the black rectangular integrated circuit with the 'MICROCHIP' logo and 'ATmega8' text, featuring two rows of pins along its longer sides.
3. Especificacions
- Model: ATmega8-16PU
- Arquitectura: 8-bit AVR RISC
- Memòria flaix: 8KB In-System Self-Programmable
- EEPROM: 512 bytes
- SRAM: 1 KB
- I/O Pins: 23 programables
- Vol. Operatiutage: 4.5 V - 5.5 V
- Maximum Clock Frequency: 16 MHz
- Tipus de paquet: 28-Pin PDIP (Plastic Dual In-line Package)
- Perifèrics: 3 Timer/Counters, UART, SPI, I2C, 6-channel 10-bit ADC, Analog Comparator, Watchdog Timer
- Fabricant: Tecnologia de microxip
4. Configuració
Proper setup is crucial for the reliable operation of the ATmega8-16PU. Always refer to the official ATmega8 datasheet for detailed pinout diagrams and electrical characteristics.
4.1. Connexió a la font d'alimentació
- Connect VCC (Pin 7) to a stable 5V power supply.
- Connect GND (Pin 8) to the circuit ground.
- Connect AVCC (Pin 20) to VCC, or to a separate filtered 5V supply if using the Analog-to-Digital Converter (ADC).
- Connect AREF (Pin 21) to the analog reference voltage for the ADC, typically VCC or an external reference.
- Decoupling capacitors (e.g., 0.1µF ceramic) should be placed close to the VCC and AVCC pins to filter noise.
4.2. Clock Source Configuration
The ATmega8-16PU requires a clock source for operation. This can be an internal RC oscillator or an external crystal/resonator.
- External Crystal/Resonator: Connect a crystal or ceramic resonator between XTAL1 (Pin 9) and XTAL2 (Pin 10). Two small capacitors (typically 18-22pF) should be connected from each crystal pin to ground.
- Internal RC Oscillator: The ATmega8 has an internal calibrated RC oscillator. This can be selected via fuse bits during programming.
4.3. Programming Interface (ISP)
The ATmega8-16PU is typically programmed using In-System Programming (ISP). This requires an AVR ISP programmer and connections to the following pins:
- RST (Pin 1): Restableix el pin.
- SCK (Pin 19): Serial Clock.
- MISO (Pin 18): Master In, Slave Out.
- MOSI (Pin 17): Master Out, Slave In.
- VCC (Pin 7) & GND (Pin 8): Power for the microcontroller.
4.4. Entorn de desenvolupament
To develop firmware for the ATmega8-16PU, you will need a suitable Integrated Development Environment (IDE) and a compiler. Popular choices include:
- Microchip Studio (formerly Atmel Studio): Official IDE from Microchip, offering comprehensive tools for AVR development.
- IDE d'Arduino: Can be used with ATmega8 if an Arduino bootloader is flashed, simplifying development for hobbyists.
- PlatformIO: A cross-platform IDE and ecosystem for embedded development.
5. Principis de funcionament
Understanding the core operating principles is essential for effective programming and utilization of the ATmega8-16PU.
5.1. Programming Workflow
- Write Code: Develop your application code in C/C++ using your chosen IDE.
- Compilar: Compile the source code into a HEX file, which is the machine-readable format for the microcontroller.
- Flash: Use an ISP programmer to upload the HEX file to the ATmega8-16PU's Flash memory. This process also involves setting fuse bits, which configure fundamental device settings like clock source and brown-out detection.
- Prova: Verify the functionality of your programmed device.
5.2. E/S digital
The ATmega8-16PU has 23 general purpose I/O pins organized into three ports: Port B (PB0-PB7), Port C (PC0-PC6), and Port D (PD0-PD7). Each pin can be configured as an input or an output, and can have an internal pull-up resistor enabled when configured as an input.
- DDRx Register: Data Direction Register (e.g., DDRB) controls whether a pin is an input (0) or an output (1).
- PORTx Register: When configured as output, PORTx controls the output state (HIGH/LOW). When configured as input, PORTx enables/disables the internal pull-up resistor.
- PINx Register: Reads the current state of the input pins.
5.3. Analog-to-Digital Converter (ADC)
The integrated 10-bit ADC allows the microcontroller to measure analog voltages. It has 6 multiplexed channels (on the PDIP package) and can convert an analog input voltage to a 10-bit digital value.
5.4. Interfícies de comunicació
The ATmega8-16PU supports several serial communication protocols:
- USART (Universal Synchronous/Asynchronous Receiver/Transmitter): For serial communication with other devices (e.g., PC via USB-to-serial converter).
- SPI (Serial Peripheral Interface): A high-speed synchronous serial data link for short-distance communication.
- Two-wire Serial Interface (TWI/I2C): A byte-oriented two-wire serial interface for connecting low-speed peripherals.
6. Manteniment
The ATmega8-16PU is a robust electronic component, but proper handling and storage are essential to ensure its longevity and reliable performance.
- Protecció contra descàrregues electrostàtiques (ESD): Always handle the microcontroller with appropriate ESD precautions, such as using an anti-static wrist strap and working on an ESD-safe mat. Static electricity can permanently damage the device.
- Emmagatzematge: Store unused microcontrollers in their original anti-static packaging or in ESD-safe containers in a dry, temperature-controlled environment. Avoid extreme temperatures and humidity.
- Neteja: Do not use liquid cleaners directly on the microcontroller. If cleaning is necessary, use a soft, dry brush or compressed air to remove dust. Ensure the device is powered off and disconnected from any circuits before cleaning.
- Danys físics: Avoid bending or stressing the pins. Ensure proper alignment when inserting into sockets or breadboards.
7. Solució De Problemes
If you encounter issues with your ATmega8-16PU, consider the following troubleshooting steps:
- Sense alimentació/dispositiu que no respon:
- Verify VCC and GND connections are correct and stable (5V).
- Check for short circuits on the board.
- Ensure the clock source (crystal/resonator or internal RC) is correctly configured and functioning.
- Errors de programació:
- Confirm ISP connections (RST, SCK, MISO, MOSI, VCC, GND) are secure and correct.
- Verify the programmer is correctly selected in your IDE.
- Check fuse bit settings. Incorrect fuse bits (e.g., wrong clock source) can prevent programming.
- Ensure the microcontroller is receiving adequate power during programming.
- Unexpected Behavior/Code Malfunctions:
- Review el vostre codi per errors lògics.
- Use debugging tools if available (e.g., simulator in Microchip Studio).
- Check external component connections and values (resistors, capacitors, sensors).
- Ensure power supply is stable and free from excessive noise.
- Sobreescalfament del dispositiu:
- Check for excessive current draw from I/O pins or short circuits.
- Ensure operating voltage is within the specified range (4.5V - 5.5V).
8. Garantia i Suport
For detailed warranty information and technical support regarding the ATmega8-16PU microcontroller, please refer to the official Microchip Technology website or contact their customer support directly. Product datasheets, application notes, and community forums are valuable resources for further assistance.
Microchip Technology Official Weblloc: www.microchip.com
