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  • Blackaddr's Avatar
    Today, 03:23 PM
    Thanks KurtE, I was not aware of that particular transfer() function, I'll go look into it. As for the the cache issue, should not the pointers to the buffers be volatile? In fact, shouldn't this be enforced by the...
    15 replies | 229 view(s)
  • Blackaddr's Avatar
    Yesterday, 01:05 PM
    @KurtE You're pretty knowledgeable about SPI and DMA. I think you also worked on the T4 beta? What do you think are the odds of us getting SPI DMA support built right in the teensyduino libraries (as far as I know it's...
    15 replies | 229 view(s)
  • Blackaddr's Avatar
    08-21-2019, 09:10 PM
    Luckily, it can be changed on the fly! To explain a little, the output driver (PAD register) settings are done on a per-pin basis rather than 'function' basis. Each pin can be configured for several different functions...
    52 replies | 2702 view(s)
  • Blackaddr's Avatar
    08-21-2019, 12:24 AM
    Be aware the 45 MHz parts have a dummy cycle between the address and the data. The 20Mhz parts don't have that
    26 replies | 5663 view(s)
  • Blackaddr's Avatar
    08-20-2019, 08:56 PM
    @DD4WH: The assignments can likely go anywhere after you've called Wire.begin() for I2C, during my testing I had them at the end of setup(). The I2S stuff starts up as soon as the I2S object is created and most people...
    52 replies | 2702 view(s)
  • Blackaddr's Avatar
    08-20-2019, 12:07 PM
    In general this is true. But you also need to consider PCB routing. Tracks with fast edges can couple into adjacent tracks where then run close and parallel. Thus, data lines that run right next to clock lines can have...
    52 replies | 2702 view(s)
  • Blackaddr's Avatar
    08-20-2019, 02:33 AM
    Hey Paul or anyone from the Beta who worked on I2C/I2S, question about this resistor. At first, I couldn't get my T4 working with my WM8731. As we already know, the WM8731 is sensitive to overly fast edges. It appears...
    52 replies | 2702 view(s)
  • Blackaddr's Avatar
    08-17-2019, 04:15 PM
    There's actually a new 4Mbit SPI now so no need for FRAM if that's enough capacity. Check out ISSI IS62WVS5128
    26 replies | 5663 view(s)
  • Blackaddr's Avatar
    08-17-2019, 12:38 PM
    Will it work? Yes and no. #1) They require a bit of startup work. You must hold SCLK low and CS# high during power on sequence, then issues a couple custom commands to reset the device. Not a big deal but you don't...
    26 replies | 5663 view(s)
  • Blackaddr's Avatar
    08-14-2019, 09:06 PM
    In this algorithm you are not using the same values over and over again so they can't be precomputed like for wave synthesis. You are taking the input complex phasor and multiplying in by another phase-shifed phasor...
    12 replies | 515 view(s)
  • Blackaddr's Avatar
    08-14-2019, 01:05 PM
    I was working on a pitch shifter for the T3.6 that implements the Ocean's pitch shifting algorithm. It is a spin on the concept of the phase vocoder. The basic process is 1) Use overlapping STFT to get the initial...
    12 replies | 515 view(s)
  • Blackaddr's Avatar
    08-11-2019, 06:05 PM
    Thanks Paul. Very much looking forward to using the Teensy 4.0 with my TGA Pro and this info will help me make an adaptor board. I presume the 100 ohm resistor on MCLK was to help absorb some reflections from the...
    52 replies | 2702 view(s)
  • Blackaddr's Avatar
    08-11-2019, 01:14 PM
    I understand that the T4 is not direct pin compatible with the audio shield as the I2S pins are in different locations. Looking through the massive Beta thread, there was some discussion about an adaptor board not being...
    52 replies | 2702 view(s)
  • Blackaddr's Avatar
    07-12-2019, 12:02 AM
    Assuming the SSOP part, Pin 22 (CSB) of the WM8731 controls the I2C address. Pin 21 (MODE) controls whether it is I2C or SPI control interface. For two WM8731s, pull or tie the MODE pin low on both chips to select I2C,...
    4 replies | 271 view(s)
  • Blackaddr's Avatar
    06-29-2019, 10:41 AM
    Kicad is great
    11 replies | 604 view(s)
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About Blackaddr

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About Blackaddr
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Engineer by day, Maker by night.
Location:
Canada
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Guitar Digital Modelling
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