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| en:avr:introduction [2010/03/05 01:30] – Translation in progress yllars | en:avr:introduction [2020/07/20 09:00] (current) – external edit 127.0.0.1 |
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| [{{ :images:avr:avr_atmega128_smd.jpg?182|ATmega128 in SMT package (TQFP64, to be precise)}}] | [{{ :images:avr:avr_atmega128_smd.jpg?182|ATmega128 in SMT package (TQFP64, to be precise)}}] |
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| AVR is a series of 8-bit RISC microcontrollers produced by Atmel. AVR follows Harcard architecture and therefore has separate program and data memory. For the program it has an internally overwriteable flash memory, for data there are static (SRAM) and EEPROM memory. Controller's frequency is usually up to 16 MHz and performance is almost 1 MIPS per a 1-megahertz cycle. | AVR is a series of 8-bit RISC microcontrollers produced by Atmel. AVR follows Harcard architecture and therefore has separate program and data memory. For the program it has an internally overwriteable flash memory, for data there are static (SRAM) and EEPROM memory. Controller's frequency is usually up to 16 MHz and performance is almost 1 MIPS per 1-megahertz cycle. |
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| The production of AVR microcontrollers began in 1997 and by now AVR is one of the most popular controllers with freelance electronic engineers. The initial success came thanks to cheap developing tools, the diversity of peripherals in a single package and low power consumption. By now, there is another reason to choose AVR: the massive amount of information and tutorials that have built up over the years. The AVR technology is inevitably aging, but to stay in the competition Atmel is also making new AVR microcontrollers with more up-to-date peripherals and 16- and 32-bit buses, first of which are from the 8-bit compatible XMega series and the latter from the brand new AVR32 series. | The production of AVR microcontrollers began in 1997 and by now AVR is one of the most popular controllers with hobby electronics engineers. Thanks to cheap developing tools, the diversity of peripherals in a single package and low power consumption the initial success was gained. Today, there is another reason for choosing AVR: the massive amount of information and tutorials built up over the years. The AVR technology is inevitably aging, but to stay in competition Atmel is also making new AVR microcontrollers with more up-to-date peripherals and 16- and 32-bit buses, first of which are from the 8-bit compatible XMega series and the latter from the brand new AVR32 series. |
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| According to the type of the application, there are several types of AVR microcontrollers, each with a different configuration. Most of the AVRs belong to the megaAVR series, which have a large program memory. To balance the megaAVR series, there is also the tinyAVR series, which have smaller packages and less features. In addition to those, there are also different series of microcontrollers designed specifically for controlling USB, CAN, LCD, ZigBee, automatics, lighting and battery-powered devices. | Based on the type of the application, there are several types of AVR microcontrollers, each with a different configuration. Most of the AVRs belong to the megaAVR series, which have a large program memory. To balance off the megaAVR series, there is also the tinyAVR series, which have smaller packages and less features. In addition to these, there are also different series of microcontrollers designed specifically for controlling USB, CAN, LCD, ZigBee, automatics, lighting and battery-powered devices. |
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| The following text describes the main features of megaAVR series microcontrollers, using one of the most popular controllers in this series, ATmega128 as an example. This controller is also in the HomeLab kit. Generally, all the AVR series microcontrollers' register names, meanings and usage is reglemented so that the examples can be used with other controllers as well by making only slight changes. The main differences are in the peripherals. The code samples of this introduction are written in assembler and C, using AVR LibC. | The following text describes the main features of megaAVR series microcontrollers, using one of the most popular controllers in this series, ATmega128, as an example. This controller is also in the HomeLab kit. Generally, all the AVR series microcontrollers' register names, meanings and usage is organized in a way to enable the examples also to be used with other controllers by making only slight changes. The main differences are in the peripherals. The code samples of this introduction are written in assembler and C, using AVR LibC. |
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| ===== Physical appearance ===== | ===== Physical Appearance ===== |
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| [{{:images:avr:avr_atmega32_dip.jpg?200 |ATmega32 in 40-pin DIP casing}}] | [{{:images:avr:avr_atmega32_dip.jpg?200 |ATmega32 in 40-pin DIP casing}}] |
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| Like all other controllers, the AVR is also packaged in some standard shell. The traditional shell is DIP (also called DIL). | Like all other controllers, the AVR is also packaged in some standard shell. The traditional casing is DIP (also called DIL). DIP is a so-called casing on legs - all the pins extrude as legs, about 5 mm in length, from the black plastic casing. DIP casing is a sensible choice for hobby applications and prototypes, because there are cheap sockets available for it, so the microcontroller can easily be replaced, should it happen to malfunction or die. The legs are also a disadvantage of the DIP casing, because it requires holes to be drilled in the circuit board. |
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| Nagu kõik teisedki kiibid, on AVR pakendatud mingi standardkesta sisse. Traditsiooniline kest on DIP (nimetatakse ka DIL). DIP on nii-öelda jalgadega kest - kõik kiibi viigud on umbes 5-millimeetriste jalgadena näpuotsasuurusest mustast plastist korpusest välja toodud. DIP kest on mõistlik valik hobirakendustes ja prototüüpide puhul, sest selle jaoks on saada odavad pesad, kust saab mikrokontrolleri läbipõlemise korral lihtsalt kätte ja uuega asendada. Samas on jalad ka DIP kesta miinuseks, sest nende jaoks on vaja trükiplaadile auke puurida. | The surface mount casings (SMT, also called SMD) are much more compact, because their pins are designed to be soldered straight to the board without the need to penetrate it. SMT microchips are in thin, coin-sized rectangular casings with pins about 1 mm long. A more precise hand and better tools are required for soldering SMT chips. |
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| Palju kompaktsemad on pindliides ehk SMT (nimetatakse ka SMD) kestad, sest neil on jalad mõeldud mitte plaadi läbistamiseks, vaid otse rajale kinnijootmiseks. SMT kestas on kiibid õhukesed umbes mündi suurused neljakandilised mustad korpused, mille jalad on umbes millimeetri pikkused. SMT kestas kiipide jootmisel on vaja täpsemat kätt ja paremaid töövahendeid. | AVRs are available in both DIP and SMT casings. The layout of the pins is designed as logically and electrically even as possible. For example, on larger chips, the ground and supply pins are located on several sides of the microcontroller, the pins for an external oscillator are near the ground pin, the bus pins are in numerical order, the communication pins are next to each other etc. AVRs digital pins are compatible with TTL/CMOS standard voltage levels. At 5 V supply voltage, 0 to 1 V means logical zero, which is also called zero, null, 0, low, ground, or GND. At the same supply voltage, 3 to 5.5 V means logical one, also called one, 1, high. This type of wide voltage range only applies to the inputs - the output voltage on a pin with no load is still 0 V or near supply voltage, depending on the state of the pin. The allowed analog voltage level on the ADC channels is 0 to 5.5 V. |
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| AVR-e on saada nii DIP kui SMT kestades. Viikusid on püütud loogiliselt ning elektriliselt ühtlaselt paigutada. Näiteks on maa ja toiteviigud suurematel kiipidel toodud mitmesse kiibi külge, välise kvartsi viigud on maa viigu lähedal, siinide viigud on numbrilises järjekorras, andmesideliideste viigud on kõrvuti jne. AVR digitaalsed viigud ühilduvad TTL/CMOS standardsete pingenivoodega. 5 V toitepinge juures tähistab pinge 0 kuni 1 V loogilist nulli, mida nimetatakse ja kirjutatakse elektroonikute kõnepruugis ka kui: null, 0, madal, maa, mätas, //ground// või GND. Sama toitepinge juures tähistab pinge 3 kuni 5,5 V loogilist üht, mille nimetused on: üks, 1, kõrge, //high//. Selline suur loogiliste väärtuse pingeskaala kehtib sisendite kohta - väljundpinge on ilma koormuseta AVR viikudel vastavalt olekule ikkagi 0 V või toitepinge lähedane. Tehnoloogiast tingituna on ka analoogpinge (ADC kanalid) väärtused lubatud sarnases 0 kuni 5,5 V vahemikus. | |
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| ==== ATmega128 ==== | ==== ATmega128 ==== |
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| Et järgnevatest näidetest ATmega128 kohta paremini aru saada, on välja toodud ATmega128 SMT kesta viikude skeem. Viikude juures on selle number, primaarne funktsioon ja sulgudes alternatiivne funktsioon. Toiteotsad on GND ja VCC. AVCC ja AREF on vastavalt analoog-digitaalmuunduri toite ja võrdluspinge viigud. XTAL1 ja XTAL2 on välise kvartsostsillaatori, resonaatori või taktigeneraatori jaoks. Viigud PB0 kuni PG4 tähistavad sisend-väljundsiinide bitte. Viikude alternatiivfunktsioonidest tuleb juttu vastavates peatükkides. | To better understand the following examples on ATmega128, there is a pinout schematic of ATmega128 (SMT package) below. Next to each pin, is a text with its number, primary function and secondary (alternate) function in brackets. Supply pins are GND and VCC. AVCC and AREF are analog-to-digital converter's supply and reference voltage pins. XTAL1 and XTAL2 are for connecting an external crystal oscillator, resonator or clock generator. Pins PB0 to PG4 mark the bits of input-output buses. The secondary functions of pins are discussed in the corresponding chapters. |
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| [{{ :images:avr:avr_atmega128_pinout.png?420 |ATmega128 pinout}}] | [{{ :images:avr:avr_atmega128_pinout.png?420 |ATmega128 pinout}}] |
