ATMega328 - TQFP

This is Atmel's high performance, low power 8-bit AVR ATMega328 microcontroller in a pint-sized TQFP package. Yes, you really can solder that.

  • 1.8-5.5V operating range
  • Up to 20MHz
  • Part: ATMEGA328P-AU
  • 32kB Flash program memory
  • 1kB EEPROM
  • 2kB Internal SRAM
  • 2 8-bit Timer/Counters
  • 1 16-bit Timer/Counter
  • RTC with separate oscillator
  • 6 PWM Channels
  • 8 Channel 10-bit ADC
  • Serial USART
  • Master/Slave SPI interface
  • 2-wire (I2C) interface
  • Watchdog timer
  • Analog comparator
  • 23 IO lines
  • Data retention: 20 years at 85C/ 100 years at 25C

ATMega328 - TQFP Product Help and Resources

Core Skill: Soldering

This skill defines how difficult the soldering is on a particular product. It might be a couple simple solder joints, or require special reflow tools.

3 Soldering

Skill Level: Competent - You will encounter surface mount components and basic SMD soldering techniques are required.
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Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

2 Programming

Skill Level: Rookie - You will need a better fundamental understand of what code is, and how it works. You will be using beginner-level software and development tools like Arduino. You will be dealing directly with code, but numerous examples and libraries are available. Sensors or shields will communicate with serial or TTL.
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Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

2 Electrical Prototyping

Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements. You will need to understand polarized components.
See all skill levels


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • BradG / about 14 years ago / 6

    Are there plans to restock this mcu? If you stock it, I will buy it.

  • Brain21 / about 14 years ago / 3

    I have 3 on order. If you don't plan on restocking, let me know so I can go elsewhere.

  • Member #200027 / about 12 years ago / 2

    +1 for Arduino Bootloader pre-installed!

    • Member #475033 / about 9 years ago / 1

      I sell this chip with the Arduino Bootloader already installed on my tindie store for a quarter more:

  • madsci1016 / about 14 years ago / 2

    Phew, just grabbed the last 8 left. I wonder when this shortage will be over.

  • bdodds / about 14 years ago / 2

    Wow, these have been out of stock for a long time! did they stop making them?

  • yu shao / about 14 years ago / 2

    I need those chips restocked! even the Digikey doesn't have them stocked.

  • EEPS / about 14 years ago / 2

    Seriously though, will these ever be restocked?

  • Jonesey / about 15 years ago / 2

    does this have the bootloader burnt onto it already?

    • tlied2 / about 15 years ago / 3

      I assume you mean the Arduino bootloader, but no, this is just the raw microcontroller. You may be interested in DEV-0921 which is the ATMega328 PDIP preprogrammed with the Arduino bootloader.

  • Member #475033 / about 9 years ago / 1

    For anyone looking for this chip with the Arduino Bootloader already installed they can be found in my store:

    This chip can be fairly difficult to get with the bootloader already installed but I offer them for a fair price with the bootloader pre-installed.

  • Member #200027 / about 10 years ago / 1

    You really should label this properly. It's the 328P, not 328. There's a HUGE difference to a beginner like me trying to load a bootloader on it.

  • Member #442795 / about 10 years ago / 1

    Is the arduino bootloader pre-installed??

  • Member #442795 / about 10 years ago / 1

    Does this chip already have Arduino boot loader pre-installed?

  • Member #251260 / about 10 years ago / 1

    Is it possible to load the Bootloader through the FTDI breakout?

  • Rival / about 10 years ago / 1

    Hi, could anyone share information about how to wire this chip in order to use the Arduino IDE to upload sketches please?

    I was the whole day trying to figure out how to upload the bootloader and once I did it I'm having problems to upload a very basic sketch...

    I already google it and there are a bunch of pages with information but nothing worked for me.


    • The directions you want to look at are here. Just double check your pin mapping as this is for a different ATMega328 package than the TQFP.

  • Jake0313 / about 11 years ago / 1

    Can this chip be programmed with Arduino if I burn the bootloader onto it? Thanks!

    • M-Short / about 11 years ago / 1

      Yes, in fact this is what we use on many of our boards.

  • Dark spirit robotic / about 11 years ago / 1

    Is this usb compiler?

  • Member #403682 / about 11 years ago / 1

    Hi, I know this page is pretty dead but i will still post. I purchased 5 of these and i have read somewhere that i can use this chip without a crystal but use the internal clock. Is this true? and does anyone have a good guide on how to flash the arduino boot loader? Any help would be great Thanks!

    • MonsterBot / about 11 years ago / 1

      Google "burning arduino bootloader using arduino" or check out the Arduino site for using Arduino as an ISP to burn a bootloader.

    • MonsterBot / about 11 years ago / 1

      Yes as well as for all other AVR's. From section 6.2.1 of the 328 datasheet listed above "The device is shipped with internal RC oscillator at 8.0MHz and with the fuse CKDIV8 pro- grammed, resulting in 1.0MHz system clock."

      The MCU will run at ~1.0MHz by default, however the CKDIV8 fuse bit can be cleared to run the MCU at 8.0 MHz using only the internal RC oscillator. Also note that Atmel specifies the internal oscillator to fall with +- 10% accuracy so if you need to generate a very accurate clock signal (usually for UART transmission), an external crystal may be required.

  • Can anyone say what are the LOW and HIGH fuse values for Atmega328 to operate at 20MHz WITHOUT bootloader, When I read the fuse from Arduino UNO it showed as LOW FUSE=0xFF HIGH FUSE=0xDE these are the values for supporting bootloader.

    • MikeGrusin / about 12 years ago / 2

      Google "avr fuse calculator" and you'll find some very good web pages to help you define the fuse bits. (Example: I believe for no bootloader, you'd uncheck the "boot reset vector enabled" option, and set the boot flash section size to the smallest option, but check the datasheet to be sure.

      • Thanks Mike.It calculated as LOW fuse=0xFF High fuse=0xDF for no bootloader option.In data sheet its not clearly given. Okay i'll take a chance and load those values :D

  • ianlee74 / about 12 years ago / 1

    I have a Boarduino that uses the ATMega328 PDIP version. I'm fairly new to Arduino and have a working project that I'd like to shrink down to a smaller PCB. Using this chip seems like a logical next step. However, I have no idea how to get my program on it. Is there possibly a ZIF type socket that I could plug into my Boarduino to do this? Is there a tutorial somewhere on how to program this chip w/o spending a ton on new programming hardware?

    • Gizmoguy / about 12 years ago / 1

      I use this chip exclusively in my projects. I use the USBTiny programmer from Ladyada, over at Adafruit industries. Make a spot to attach a 6 pin ISP header to your board and upgrade to Arudino 1.0 for direct programming from the Arduino IDE. You can also program it through the Serial pins using a FTDI cable. All programming has to be done after you solder it to your project unless you build a programming board using POGO sticks.

  • saif / about 13 years ago / 1

    Does anyone know this chip is ATMega328 or ATMega328P?
    Heading and description indicates ATMega328 but in the product picture which shows like ATMega328P.(as a general rule we can only believe the product descriptions rather than picture while shopping anywhere :))

  • tommyschw / about 13 years ago / 1

    I know someone else mentioned this, but I think a breakout board would be great for this. I know there are PDIP versions available, but I would like to proto this with a breakout board and then when I am finished put it on the final board.

  • floppypond / about 13 years ago / 1

    It'd be nice if this part were in your eagle library :)
    (maybe it is and I'm blind?)

    • KirAsh4 / about 13 years ago / 1

      It's the same as the 168. 48/88/168/328 are the same, just 4/8/16/32K respectively.

  • Gary D. / about 13 years ago / 1

    Restock Please !! I cant amaze you with my new design without these badboys. Trust me you will like my article... I think... I guess I could go the PIC route.

  • SomeGuy123 / about 13 years ago / 1

    This product page is like a desert with all these droughts.

  • Arrowofdarkness / about 13 years ago / 1

    Any chance of getting these back in stock? I know you use them in your own products, but these things seem to sell like hot cakes, so ordering higher quantities of them might not be a bad idea. Their way, they wont be in stock for long! ;)

  • cameraninja / about 13 years ago / 1

    Yay! Got a couple since they're back in stock!

  • WTF? They're out of stock all the time! I don't need one, but thousands do.

  • Allan4 / about 13 years ago / 1

    Sparkfun, when you have it back?

  • Sam R. / about 13 years ago / 1

    Are you guys going to add this to your Eagle Library? I can't seem to find it....

    • Young Maker / about 13 years ago / 1

      its in the eagle library-- the 168 or whatever is, just rename it, they have the exact same pinout

  • Member #98770 / about 13 years ago / 1

    Finally, these babies are back in stock. THANKS sparkfun!!!!
    Its awesome for us who followed your tutorials and want to move towards arduino+SMD-packaging :)

  • Young Maker / about 13 years ago * / 1

    digikey has 19,000 so why don't you..?
    Atmega TQFP

    • we aren't digikey.
      the majority of ours are slated for production. we use these in a lot of designs.

      • Young Maker / about 13 years ago * / 1

        Ahhh thats why! ill order an arduino pro- thats pretty much what i was gonna do with it. But still- it would be nice to make my own TQFP board to lean how to solder them. hmm simon kit fist
        EDIT Yay! you got some!

  • Ritch / about 13 years ago / 1

    SFE Library number?

  • I think that its funny that 1 year ago people were wondering when these will be restocked. And they are still waiting...

  • judetheobscure / about 13 years ago / 1

    Heads-up everyone: Mouser finally got a huge shipment of these in - I bought six so hopefully that will keep me busy for awhile :)

  • Beta / about 13 years ago / 1

    Can anyone tell me what the fuse setting for this are? I want to burn the Arduino bootloader on this chip, and if necessary, reset the fuses to run it at 5V @ 16MHz for my project. However, I don't want to have to sacrifice board space for the ATMega with the Arduino bootloader pre-burned, because that one is only sold in a PDIP package.
    I know that there is a lack of supply of these chips at this time, but I think that once their back in stock and Atmel has things sorted out, it would be a good idea to sell these chips with the Arduino bootloader and corresponding fuses pre-burned, at a raised price, just as you did with the PDIP version of the chip. This would give people with less coding experience and more soldering experience the chance to embed a microcontroller in their project, whilst saving board space and retaining the ease of programming in the Arduino environment.

    • Kuy / about 13 years ago / 1

      I think it goes without saying that if you're laying out your own board, you should include a 6-pin ISP header to program the chip in-situ (that is, of course, what ISP stands for...) An ISP header will also give you debugging ability via the debugWire pin and a matching Dragon or other kit.
      Flashing a bootloader to a chip doesn't require any programming experience, in fact I believe the Arduino IDE has a one-click option for it.
      Moreover, if you have the soldering skills to work with TQFP, maybe it's time your programming skills catch up? :-)

      • MoriFi / about 13 years ago / 1

        I use both AVR and arduino for my programing they are both good arduino is a little easer to use, AVR is a little more powerfull.

  • Mure / about 14 years ago / 1

    This chip is almost mythical, you can't find it anywhere...

  • roybean / about 14 years ago / 1

    Will this thing run on 3.3v at 16mhz? I looked at the datasheet and i get hints that to run at 3.3, you have to do it at 4mhz.

    • NewsparkFunCusty / about 14 years ago / 1

      3.3v @ 8MHz. I use these directly with a programmer, and the arduino hex file it compiles, run it with its internal resonator @ 8MHz. Compile it with any 8mhz board selected. goto your temp folder for arduino and get the hex file and bam...<br />
      And you get 2k more memory to play with too, and still run arduino software. =)

  • Roach / about 14 years ago / 1

    What happened to the auto-notify feature? Did it disappear with the site redesign?

  • RobitTechnology / about 14 years ago / 1

    How can i found this chip urgently

  • Travster / about 14 years ago / 1

    Any feedback on this shortage from SFE??? Newark says "Lead Time 57 days", that's the most info I've seen...

  • wiggles / about 14 years ago / 1

    @ROACH, I never got an email notification, it could be that not everyone got one and therefore aren't aware they're available.

  • Roach / about 14 years ago / 1

    I swear to God. Between receiving the re-stock notification and confirming my purchase, start to finish: 20 seconds. Then I cam back a half-hour later. Looks like I'm the only one buying these! Has the demand mysteriously disappeared?

  • BT / about 14 years ago / 1

    Seems that there is a shortage of '328 parts. The AVR-Chat group has a current thread concerning the lack of availablility.
    Speculation is that Atmel doesn't package their own chips (plastic and pins) and that an increasing demand for contract fab facilities has created a production backlog.

  • pmason / about 14 years ago / 1

    I got the auto notify email too and checked the item page pretty much immediately and it was out of stock. I wanted to buy two for a couple arduino projects. Did one person buy them all up or what? Does anyone know a way to buy the Atmega328 tqfp currently?

  • wiggles / about 14 years ago / 1

    Just got an email saying they were in stick, did you really manage to sell all 4800 in under an hour and a half? I knew these were in demand but jeez.

    • S.Goff / about 14 years ago / 1

      I, too, got just such an email, and am dismayed that they are already out of stock just 2 hours after receiving the mail. It would be nice if there could be a quantity cap for these, so they don't get snapped up in huge numbers by people using them for commercial products or production. Leave some hanging around for those of us doing small quantity prototyping and experimentation, eh?

  • iklln6 / about 14 years ago / 1

    there should be a limited number per customer on these things. send the distributors to digikey. or a set with max order #, and a set with min order #, because this is an unfortunate shortage :(

  • Aerodyno / about 14 years ago / 1

    clearly some other distributor snapped them up...

  • yu shao / about 14 years ago / 1

    I just bought 10 of them 2 days ago, and it goes out of stock next day. Lucky me. But the vibrator is out of stock again, I still can't complete my project.

  • kvan / about 14 years ago / 1

    There was 400 stocked the other day. Where did they go?

  • DogNo7 / about 15 years ago / 1

    Neato, but do you have a breakout board so I can use this with a solderless breadboard?

    • tlied2 / about 15 years ago / 1

      A PDIP-28 version of this MCU is available as COM-09061. PDIP works well with breadboards.

  • TwirlyWhirly555 / about 15 years ago / 1

    As the chip does not have the arduino bootloader could it be put on the chip so it could be use with arduino

    • tlied2 / about 15 years ago / 1

      Yes, pull the ICSP pins out to a header and use an AVR programmer with the Arduino IDE to burn the firmware over ICSP.

Customer Reviews

4 out of 5

Based on 1 ratings:

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Its the atmega328!

What could one expect of this chip? it is the brain of a great many devices and project. if you need a microcontroller that is small, reliable and comes with a great deal of documentation and examples this is pretty much THE microcontroller most grab for.

I use this microcontroller the most for portable projects and clocks thanks to the great control it gives me through its timers and the ability to shut down unused parts to save on power.

There is a but however, tough as great as this chip is it is a bit of an old one. compared to the modern XMega it is just not as powerfull as it used to be.