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Since some months, everyone can buy a board with this IC.

It is compatible with the ATMega328 and has some features like 12bit ADC (instead of 10 bit), DAC, unique ID and also 32MHz.

But I can't find it in the "normal" shops. Also on the LCSC it is not available. Only in this shop: https://www.electrodragon.com/product/5pcs-logicgreen-lgt8f328p/
For 0.68$ compared to the 2$ for the atmega326P-AU of the other electronic parts shops (it is cheaper than the cheapest attiny with ADC!)

So the question. Is this chip just a clone for private use or can it be used as official alternative to the more expensive and original ATMega328?

3 Answers 3

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My understanding is that it is legal since it is just engineered to be (somewhat) compatible with ATmega328p but their difference are substantial if you deep dive.

It has a RISC core and its core instructions are quite different from ATmega328p. Most multi-cycle instructions are replaced by single-cycle instructions or less cycle instructions. And the core runs at 32Mhz from 1.8V-5.5V.

The peripheral registers are largely (backward) compatible with ATmega328. However, LGT has more or advanced peripherals.

  • 2 16-bit timers, with capture and compare output
  • ADC has 12 bits instead of 10.
  • DAC, so you don't need PWM to emulate DAC.
  • 9 high current PWM. 3 complementary PWM with dead band control.
  • PGA 1x-32x differential amp. Which saved me 1 op-amp.
  • 16 bit computing accelerator/Co-processor.
  • High and adjustable current GPIO (so you can light up LEDs without current limiting resistors). These peripherals provide lots of additional registers for control and status reporting that don't exist on ATmega.

Development environment is also different. The best way for hobbyists to develop on this chip is either using LGT Arduino Core but not ATmega328 Arduino Core: https://github.com/dbuezas/lgt8fx (Arduino IDE) or https://community.platformio.org/t/how-to-add-lgt8fx-board/13294 (PlatformIO) Or you can use their official SDK for development which is very different from AVR's environment.

LGT8F328p also has SSOP20 and LFP48 package offering smaller or larger number of GPIOs, which are not so well known by DIY community since they are not similar to ATmega328p.

So in general LGT is a different, forward engineered chip and highly unlikely a direct silicon clone copied by reverse engineering.

In general having peripheral registers and pin compatibility are not illegal, unless the IP core of the peripherals are stolen from ATmega328p. And since CPU instructions (and clock trees) are quite different, if assembly language is used for development, developer would likely feel they are two distinct MCUs. It is just that a C compiler and Arduino framework can hide those details and make them similar.

However, the laws and regulations differ across countries and states so I am not sure if that applied to all markets. And there is natural murkiness in what is an IP and what is not. In software, API similarity could result in infringement but in the world of MCU pin compatibility would not, despite they are both "interface similarity" issues.

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Legal or not, I DO NOT reccomend this clone. It is similar and compatible to some extend but it lacks features like an EEPROM. With fuses you can only reserve some FLASH to emulate an EEPROM. Thus have less space for your code.
Also the manual is only available in chinese. There are english translations but those are hard to read as the layout got screwed up.
It has some new features that sound great but I would not see them as replacement for the ATmega328P from Atmel/Microchip.

I bought an Arduino clone with LGT8F328P by accident. I find it barely usable as there are itches here and there which I don't want to deal with.

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    time has passed and this alterative has become more and more popular, documentation and even Arduino support appeared. Having successfully used it in a product with no more headaches (including after-sales) than the Ex-Atmel Microchip counterparts, I think this answer could use some updates.
    – Bigger
    Commented Dec 4, 2022 at 13:48
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As legal as any other clone CPU / MCU. See

In short: if you copy the silicon design it's illegal. If you create it yourself from the ground up it's legal.

However, IANAL, so don't quote me on that.

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  • Yes, I can remember the Cyrix fight! If I remember it correctly, it was not 100% compatible and a "Windows bug" made the OS working only on Intels, right? It would be nice to find out why this processor is only sold by this seller and not from digikey, farnell or mouser.
    – Adriano
    Commented Nov 11, 2019 at 16:55

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