Forum Rule: Always post complete source code & details to reproduce any issue!

Search:

Type: Posts; User: hstone

Search: Search took 0.00 seconds.

  1. GPIOD_PDIR set to 255 (instead of 0) when PTD0-PTD7 declared input pins on T_3.6

    Why GPIOD_PDIR becomes 255 as soon as pins PTD0-PTD7 (PORTD0-7) become input??
    Should not that be 0?

    for Teensy 3.2 GPIOD_PDIR becomes 0
    for Teensy 3.6 GPIOD_PDIR becomes 255

    Code
    const...
  2. @Frank B, Yeap you are right. I need to read a...

    @Frank B, Yeap you are right.
    I need to read a few 8-bit values (from 8 GPIO pins) as fast as possible (e.g. 24 Mhz) & save in memory & process :)
  3. @UhClem : Thanks for the tip! @Frank B (#21): ...

    @UhClem : Thanks for the tip!

    @Frank B (#21):
    Actually I am not really interested in pin toggling, but more on how fast I can read GPIO (e.g. how speedy digitalReadFast() is).
    I just thought...
  4. If I am correct GPIO access is at F_CPU speed,...

    If I am correct GPIO access is at F_CPU speed, not F_BUS speed ... (If i recall right)
  5. @ defragster I use Teensy 3.1 @ 96 Mhz, just...

    @ defragster
    I use Teensy 3.1 @ 96 Mhz, just like as Frank B (Teensy 3.2 @ 96 Mhz)

    CPU is T_3.1/3.2
    F_CPU =96000000
    ARDUINO =10801
    F_PLL =96000000
    F_BUS =48000000
    F_MEM =24000000...
  6. correction: digitalWriteFast() is SINGLE CYCLE...

    correction:

    digitalWriteFast() is SINGLE CYCLE that is 96 Mhz (teensy @ 96 Mhz)
    toggling which requires 2 digitalWriteFast() is ~ 48 Mhz.
    So in Frank B's, 3 Mhz result, the performance is from...
  7. Dear all, thanks for replying! ...

    Dear all, thanks for replying!

    @Theremingenieur Yeap, i did not know loop() had such an overhead ...

    Using registers is always faster, sure, but I recall Paul saying digitalWriteFast() could...
  8. STRANGE GPIO speed perfomance with digitalWriteFast() (ring oscillator example)

    I am very interested in maximum GPIO speed for teensy 3 series.
    I am aware from previous posts, that digitalWriteFast() can be extremely fast on teensy 3

    I came across an interesting comparison...
Results 1 to 8 of 8