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I'm new to stm32 micro controllers. I read in STM32F103 data sheet that it has 3 ADC converters capable to perform up to 1Msps each. Is it possible to utilize these 3 converters to sample 1 channel up to 3 Msps ? I'm guessing it is possible if I start conversion for each converter sequentially with time difference 0.333us between one converter to another. So I get 3 conversion result from 3 converter for every 1us duration.

Is it feasible ? please advice. Thanks.

artless noise
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night_coder
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  • What is the I/O rated for? you might be able to sample at 3msps but may be limited to a 1mhz frequency on each input (which wont scale). I would try feeding it a 1mhz or perhaps 1.5mhz signal and see what you see. – old_timer Jun 21 '12 at 13:47
  • ADC's will have a sample and hold that can be related to the max input frequency, if the 1msps limit is due to the sample and hold then you wont benefit by exceeding that, you may even get goofy looking results depending on what method they use for the conversion. http://en.wikipedia.org/wiki/Analog-to-digital_converter – old_timer Jun 21 '12 at 13:50
  • I'm going to sample just single line of signal. If the line is externally connected (paralleled) to 3 input lines of each converter will the result still distorted ? – night_coder Jun 22 '12 at 07:56
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    There is a "fast interleaved mode" for two channels (see the STM32F10x reference manual). – starblue Jun 22 '12 at 10:52
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    starblue may have answered your specific question, in general though connecting the inputs in general does not insure the signal is below the per input frequency which is what I am trying to point out, doesnt matter if it is one input or three if you exceed the input frequency there is no guarantee it will do what you want it to do. as starblue has done for you, read the manual... – old_timer Jun 22 '12 at 13:30

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STM32F4 have native triple-interleaved mode, also each channel is possible to work at 2.4 MSPS. Also no need in external shorting of 3 pins, just ADC1-ADC3 are setup for one chn. So the speed could be 7.2-8.4 MSPS (thereis an example in STM32F4Discovery program pack)

DrG
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