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Thread: Teensyduino 1.48 Beta #3

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  1. #11
    Senior Member+ manitou's Avatar
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    Quote Originally Posted by PaulStoffregen View Post
    PulsePosition hasn't been ported yet. It's filled with FTM/TPM timer code. Only Teensy 3.x & LC have those timers. NXP put different timers in this IMXRT new chip.

    I will eventually port PulsePosition, maybe to the FlexPWM timers, maybe to the quad timers. But that's not going to happen for the 1.48 release.
    I have a proof of concept sketch for PPM input portion of PulsePosition for the T4 using quad timer, see
    https://github.com/manitou48/teensy4...ter/ppminq.ino
    This was based on earlier sketch/discussion that used T4 quad timer. As with that sketch, I was never able to get overflow (TOF) interrupt to work on T4 quad timer, so I used timer compare (0xffff) to count timer overflows. In the ppminq.ino sketch the T4 quad timer is clocked at 37.5 MHz. I tested with a T3.2 running PulsePosition LoopBack example with PPM output on T3.2 pin 9 jumpered to T4 capture pin 11. The printed output looks good.
    Code:
    1086 :  600.03  1500.03  759.23  1500.03  1500.00  1234.56  
    1087 :  600.03  1500.00  759.25  1500.00  1500.03  1234.53  
    1088 :  600.03  1500.03  759.23  1500.03  1500.00  1234.56  
    1089 :  600.03  1500.00  759.25  1500.00  1500.03  1234.53
    You can flip polarity with TMR_SCTRL_IPS.

    Now to see how to get the T4 to generate PPM out pulses...
    Last edited by manitou; 10-24-2019 at 10:06 PM.

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