Forum Rule: Always post complete source code & details to reproduce any issue!
Page 4 of 4 FirstFirst ... 2 3 4
Results 76 to 84 of 84

Thread: Suggest next Teensy with Cortex M7

  1. #76
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    Posts
    15,441
    Many questions. Here's some quick answers...

    Only NXP can say for sure about their memory design choices, but it's easy to imagine the likely answer: cost.

    I need to be careful about the NDA, so I'm not going to comment about questions involving the chip's details or anything I might know about their plans for future chips in this product line.

    External SDRAM is one of the very difficult choices for a new Teensy. The situation is similar to Teensy 3.6, where FlexBus consumes many of the I/O pins and makes several important features unavailable. So I'm leaning against SDRAM (or keeping those pins unused). It simply costs too much, in terms of lost functionality.

    My hope is to move towards integrating conditionally compiled semaphone or mutux support into the core library and many of the most commonly used Arduino libs. I do not intend to make any RTOS mandatory, but quite a lot could be done in the many libraries so they work much better when used with an RTOS. This is the sort of thing best discussed on its own thread. But I will say right now, the 2 limiting factors are dev time to do this, and having RTOS users willing to help test unstable/alpha/beta code. Both of these always seem so elusive...

    Release of bootloader chips and a reference board will almost certainly look similar to prior times. Never before have I managed to get these done right at the Teensy board's release. There's always a ton of stuff to do leading up to the release, and then usually a few months of highly urgent software work following. I'm pretty sure a first Cortex M7 board will be similar.

  2. #77
    hm.. ok, so i basically need to stick with my teensy 3.2 until the core libs get rtos support (luckily i can wait)
    too bad i can't help you with testing (and indeed, this is a bit offtopic)

    regarding the sdram: will there be a possibility of a teensy version with it and one without? (like you did with the usb host on t3.5/t3.6)

    tbh, i'm looking forward to what the future brings with the teensy 4.0!

  3. #78
    Senior Member defragster's Avatar
    Join Date
    Feb 2015
    Posts
    4,809
    Interesting the T_3.6 has been out a year now and RTOS hasn't been ported to it? It would be a big step up from the T_3.2 RAM and Speed wise - plus flash and extended hardware. The multitasking support used is part of the processor design - and the T_3.5 and 3.6 seem to have that functionality as least as good - there are one or two other real time switchers in progress on the forum that seem efficient and effective.

    The " (like you did with the usb host on t3.5/t3.6) " was a natural fallout of making a new Teensy that was still 5V tolerant ( the T_3.5 ) and the enhanced T_3.6 that is not 5V tolerant but adds more features and capacity - one of which was the usb host support. The MCU's share the same package layout to the point the same PCB is used - where the T_3.6 can do usb host and the T_3.5 without that hardware exposes two added analog pins.

  4. #79
    Senior Member
    Join Date
    Jul 2014
    Location
    New York
    Posts
    430
    Been reading about level shifters. The new board will not be 5v tolerant we know that. But what level shifters can be used and for what pins. Are different ones more appropriate for I2C, SPI, digital pins etc? Bi-directional?

  5. #80
    Senior Member MichaelMeissner's Avatar
    Join Date
    Nov 2012
    Location
    Ayer Massachussetts
    Posts
    2,441
    Quote Originally Posted by mjs513 View Post
    Been reading about level shifters. The new board will not be 5v tolerant we know that. But what level shifters can be used and for what pins. Are different ones more appropriate for I2C, SPI, digital pins etc? Bi-directional?
    Note, I'm a software guy, but I have to imagine the same issues will hold for the new chip as well as the current LC/3.6 chips. Given that the new board will still be 3.3v, any solution you use now should work with the new board. In general, it is better if the communication is unidirectional (i.e. a pin is an output pin or an input pin and never both). If you have to use bidirectional level shifting (i.e. i2c, spi), it can slow things down, and there are various caveats about its use cases.

  6. #81
    Senior Member
    Join Date
    Dec 2016
    Location
    Canada
    Posts
    676
    mjs513, im prepping the 3.5 to be slave ready when the 4.0 comes out, keep posted in my other thread

    level shifters not needed

  7. #82
    Senior Member
    Join Date
    Jul 2014
    Location
    New York
    Posts
    430
    @tonto81. Which one

  8. #83
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    Posts
    15,441
    Probably this thread.

  9. #84
    Senior Member
    Join Date
    Jul 2014
    Location
    New York
    Posts
    430
    @PaulStoffregen. Sorry for the delay in responding, had major problem with computer. Thanks, will go through it. Think this is related to a couple of other threads as well now that I see the one that you referenced.

Posting Permissions

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