How to find the right processor?

berger · ‎2016-03-02

Posted on March 02, 2016 at 15:37

My particular

question

is

I need a

processor that can

quickly

measure the

analog voltage

i.e.

,

it has

the fastest

ADC

or

preferably more

,

which may be combined

in

one

.

I find STM32F303 with 4x 5MSPS ADC, but

perhaps even

better choice

?

In general

There is

a

list

in

which

it

was

found,

which type of

MCU

has the fastest

DAC,

most

DMA channels,

and so on

?

AvaTar · ‎2016-03-02

Posted on March 02, 2016 at 16:17

Perhaps a DSP would serve your (undisclosed) purpose better.

These class of controllers are designed for high data throughput rates (including analog data), with high peak performance in short cycle loops.

With a general-purpose MCU like Cortex M, you might get problems to process data as fast as they accumulate - at least for your proposed rates.

berger · ‎2016-03-03

Posted on March 03, 2016 at 14:01

Thanks.

DSP bit of overkill, its place in a continuous analog signal processing.

My app is measuring, takes a sample and processing time can be slow

In real, I have a professional version in which external high speed DAC and ADC

and considering a version for guests, version with MCU+DAC and DAC in ohne chip.

AvaTar · ‎2016-03-03

Posted on March 03, 2016 at 16:26

In your initial post, you mentioned ''

5MSPS ADC, but

perhaps even

better

''. This suggested higher data rates.

Data rates of 100kSPS or below are surely not a problem for a Cortex M.

BTW, the number of separate ADC peripherals is not equivalent to the number of ADC channels. In fact, the maximal number of channels is often the same. Multiple ADCs use the same input pins. Using an ''interleaved'' mode, this allows for a higher effective sampling rate on a single analog input. This feature is useful (and often used) for motor control or power converters.

I'm not sure about your requirements, but the number of DACs seems the limiting factor. I know of no MCU with more than 2 channels - but I didn't research this lately. The quality of DACs is pretty consistent across the STM32 family.

Number of DMA channels seems less of concern. Usually, one DMA channel is used to pick up one set of values from all the configured ADC channels in the scan sequence. That would probably mean 1 DMA channel for ADC, two for DAC (since they have separate DR registers).

In general, ST has a kind of ''online selection table'' for the STM32F3 family there:

http://www.st.com/web/en/catalog/mmc/FM141/SC1169/SS1576