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I am in the process of selecting a microcontroller to interface (~30 signal lines) to an FPGA that operates at 1.8V voltage levels.

I have found NXP's Cortex M0's to operate down to 1.8V which is great, but the bulk of Cortex M3 chips out there have a minimum operating voltage of 2V.

Should I restrict myself to the M0's? Or should I just use level translators? Are there Cortex M3 implementations that have an I/O voltage of 1.8v?

Note that I do have other voltage levels available on the board, but i just need the micro's I/O voltage to be compatible with 1.8V logic.

cksa361
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2 Answers2

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NXP has 74 different Cortex-M0 controllers, so if the M0's performance is good enough (they run at 50 MHz maximum), then you'll probably find a type which has the right features for your application.

If you want more options or need a higher performance you could go for the Cortex-M3 combined with a GTL2000.

enter image description here

The GTL2000 offers you 22 fast channels which you can use unidirectional or bidirectional, and as you can see in the diagram you can interface with several voltage levels with a single device. The GTL2000 can work with levels between 1 V and 5 V on either side. This is a cost-effective solution if you have many lines between the controller and FPGA, but there are also versions with less transceivers if you can do with less. The GTL2010 is a 10-channel version.

stevenvh
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it depends, read the microcontroller manual and find out what's the voltage level that specified in the manual. Not only the voltage level, for a example TTL means lots of electrical specifications than just 5V.

see : http://infosys.co.kr/e002/e002-s01.html

so guessing that you talking about a TTL microcontroller interface, you need to have at least 2.0 to represent logic level 1.

So the answer is YES. You need a level converter.

Standard Sandun
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