Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 6 of 6

Thread: MCU trends

  1. #1
    Senior Member pictographer's Avatar
    Join Date
    May 2013
    Location
    San Jose, CA
    Posts
    665

    MCU trends

    Interesting article on trends and trade-offs in MCU design: https://semiengineering.com/the-mcu-dilemma/

  2. #2

  3. #3
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    Posts
    21,288
    ARM announced Cortex-M55 this week, also with vector processing for machine learning & signal processing. It's almost certain to become Teensy 5.x... in 2-3 years when chips become available.

  4. #4
    Senior Member+ Theremingenieur's Avatar
    Join Date
    Feb 2014
    Location
    Colmar, France
    Posts
    2,551
    Priorities in that domain are obviously changing. Almost nobody talks any more about improving the analog building blocks in mixed signal MCUs - it's rather the opposite: Powerful integrated ADCs and DACs tend to be eliminated or externalized. The Teensy 3.2 had 2 16bit ADCs with 12 or 13 useable bits resolution and one 12bit DAC with useable sampling rates slightly above 500kHz. The Teensy 3.5 and 3.6 had even two of these DACs. I had hoped for >1MHz bandwidth and at least 14 if not 16 useable bits resolution on 4 ADCs and 4 DACs in their successors, but we got a T4 without any DACs at all and with degraded ADC resolution.
    That's highly frustrating for old farts like me who still dream of full universal analog (from DC to video signal range) and digital integration on one single chip. Time for me to retire?

  5. #5
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Location
    Germany NRW
    Posts
    6,163
    You don't want the noise from all the other circuits on the chips. External circuits can do this much better and are not that hard to use.
    Maybe some day a company makes a easy to use addonboard for old farts like us. For Audio, there are plenty.
    Then, more and more becomes digital. The use-cases are not that much. Video is digital nowadays, too. No need anymore for ntsc, fbas, vga and so on. And audio - everything between in and output is digital anyway.
    Last edited by Frank B; 02-14-2020 at 11:07 AM.

  6. #6
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    Posts
    21,288
    I too had hoped for DACs. Believe me, I've repeatedly begged for DACs from my contacts within NXP. We are getting 1 DAC in the next chip, which is a lot better than none, but I'm pretty sure it's not because of anything I said. I'm pretty sure they decide the features based on requests from only very large customers and maybe by looking at what ST is up to with their STM32 chips?

    There are 2 unfortunate trends affecting analog. It's well known that as mosfet channel lengths and other silicon process features shrink, the speed and amount of digital circuitry scales up, but the quality of analog circuitry scales downward. The same is true for flash memory, which is why use of external QSPI flash chips is becoming the norm with these fast parts. But memresistor technology may become possible in the future as things keep scaling even smaller...

    The other trend looks like human factors. My best guess is iMXRT was mostly designed by NXP's teams who've worked on the iMX application processors, rather than the people with experience from Kinetis, HC08 and other microcontrollers. Some of their analog design decisions, like not bringing VREFH to a pin, seem downright negligent. Specs for the next 1170 chip are still under NDA, so I can't comment on details, but I will say it does look like they're learning some lessons in analog.

    But the dream of a chip with very a high speed CPU and high precision analog on the same silicon die runs counter to the reality of semiconductor physics. As silicon scales to smaller feature sizes, only digital circuitry tends to reap the benefits.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •