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Arduino board has a microcontroller called Atmega328. I wonder if it is CMOS or TTL. I dont know how to understand it from the datasheet. Second question is on the Arduino board there are other chips. Are they all TTL or CMOS? How can I know?

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    \$\begingroup\$ "How can I know?" - but why would we want to? Anything we need to know should be in the datasheets. For 99.99% of uses, it could filled with little blue imps - so long as it does what the datasheet says. \$\endgroup\$ – RedGrittyBrick Nov 7 '13 at 15:17
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    \$\begingroup\$ I always thought it was "magic smoke" ... \$\endgroup\$ – Spoon Nov 7 '13 at 16:04
  • \$\begingroup\$ possible duplicate of Which logic gate family is used in a PC? TTL or CMOS? \$\endgroup\$ – Joe Hass Nov 7 '13 at 17:27
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All the key facts about a chip should be contained in its datasheet. This should always be your first port of call when researching things.

Atmega328 datasheet.

Search for "CMOS". First hit is page 5:

"The ATmega48PA/88PA/168PA/328P is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture".

Bonus answer: a quick look at the Arduino UNO schematic shows three different voltage regulators, and an LM358D used as a comparator, all of which are considered "analog" parts and neither CMOS nor TTL.

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  • \$\begingroup\$ intersting. i thought any component nowadays should be eirther ttl or cmos ?? \$\endgroup\$ – user16307 Nov 7 '13 at 15:21
  • \$\begingroup\$ @user16307 Where did you get the impression that any component must be either TTL or CMOS? \$\endgroup\$ – Anindo Ghosh Nov 7 '13 at 15:39
  • \$\begingroup\$ i mean in a circuitry why to use several different locig gates so one has to use interfaces to make them work together. where am i wrong?:( also isnt it cmos and ttl the most common ones? \$\endgroup\$ – user16307 Nov 7 '13 at 15:42
  • \$\begingroup\$ "There are more things in heaven and earth than are dreamt of in your philosophy": TTL/CMOS is not an exhaustive classification! Semiconductor design has a fairly sharp demarcation between digital and analog, and analog devices may comprise whatever mix of bipolar and FET transistors they need to go the job. You're correct that you don't get TTL and CMOS on the same device, and a larger system will stick to one of those two, but there are more kinds of chip! It's a bit like saying all fruit is either apple or orange. \$\endgroup\$ – pjc50 Nov 7 '13 at 15:45
  • \$\begingroup\$ Further upsetting this worldview: en.wikipedia.org/wiki/Logic_family It appears that a variant of ECL is still in use: focus.ti.com/lit/an/slla120/slla120.pdf but otherwise digital is almost always CMOS. \$\endgroup\$ – pjc50 Nov 7 '13 at 16:07
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The Atmega328 processor is CMOS. The other stuff is whatever the board designers decided to use, but most likely CMOS. However, instead of asking for heresay, go look at the schematic and BOM and see directly.

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