Electronics > Projects, Designs, and Technical Stuff
Interfacing high speed ADC to microcontroller
splin:
If you want to use an STM32F4 then I highly recommend reading this:
http://cliffle.com/article/2015/06/11/matrix/
It's the third part of a series on driving an an 800 x 600 VGA display with an STM32F407 which goes into some depth on the STM32F4 DMA. He achieves 40MSPS memory to GPIO on a 168MHz part using the DMA in memory to memory mode. Although perhaps not directly useful for your use case, it provides some good information on the DMA implementation on the F407 whilst being succinct and refreshingly well written. I wish I could communicate 10% as effectively...
Most interesting is the amount of non-documented (by ST) stuff he covers and the real world behaviour. I suggest reading all parts - it shouldn't take long - as an excellent insight into problem solving and working out what the documentation fails to tell you.
tszaboo:
--- Quote from: splin on April 17, 2019, 02:53:01 am ---The LPC4370 seems to be a no-brainer given that a 30MSPS 12bit ADC alone will likely cost you more - at Digikey the 40MSPS MAX1421ECM+D costs $7.24 @ 1K compared to $6.4 for the LPC4370FET100E. You will need to add an SPI FLASH but they are fairly cheap and physically much smaller than most standalone ADCs.
--- End quote ---
Yes, I think this is what I'm going to present as the easy solution. The ADC is in it, has a margin for the sampling speed, and probably lower power overall than driving an entire bus on the PCB, lower component count and size. I just completely forgot about this part.
--- Quote from: ejeffrey on April 16, 2019, 07:52:49 pm ---With an MCU you probably have to scrap the project and start over with an FPGA, or at the very least do a complete redesign with multiple interleaved MCUs.
--- End quote ---
This is already the redesign part. We have a prototype operated at 5 MSPS, and they found out that is too slow. The firmware guys are still trying to do equivalent sample method to get some more data, but it seems that the signal is not that repeatable, at least not to 12 bit.
jonroger:
Looks like the NXP LPC-Link2 can act as an evaluation board for the LPC4370.
tszaboo:
By the looks of it, they can do equivalent sampling, so I dont need to make an entirely new project out of it.
Solving hardware problems by firmware again.
Doctorandus_P:
The Cyrpess FX2 series uC are a quite lowly 8051 derivative (They never seem to die) but it has a quite nice feature to stream bulk data to an USB interface quite rapidly, but it cops out at (I think) 24MSps. But what do you expect for that price? It's quite popular in EUR7 logic analysers and entry level USB scopes.
The newer FX3 series does the same trick, but on USB3 and development boards cost around EUR 60.
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