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Thanks

Would you point me to somewhere that describes this TDM bug you mentioned here?

Here is an interesting online source that might help calibrate things the old fashion way. Can you touch the PCM3168A continuously without pain, or only for short periods?

Good information. So for free air-unheatsinked, using the spec'd Junction-to-case thermal resistance of 7.7 C/W and the typical spec'd power dissipation of 1.16 W puts the junction temperature at about 74 C - well below the spec'd maximum Tj of 150 C. But 65 C is very hot to the touch. But if...

The CS42448 does run very hot. The CS42448 DOES NOT have a thermal power pad on its bottom side, however. Since the PCM3168 has a thermal power pad, I was hoping it would run much cooler if properly connected to a good ground plane on the PCB. I can't tell from your photos, but am I correct...

I am in the process of retrofitting an existing PCB that currently uses the CS42448. It looked pretty straightforward to me, so the fact you got it working is good confirmation. FYI - One interesting observation is that the nominal supply current for the PCM3168 digital 3.3v supply is 162mA. It...

That is what I was looking for. I was wondering how you handled the RST pin. Thx

Do you have a code snippet that you can show that uses your PCM3168 control object to setup the Codec?

I know that DMA prefers 32byte aligned arrays and I have successfully used __attribute__ ((aligned(32))) when I define DMAMEM arrays. I also am aware that the cache needs to handled properly when doing DMA to/from DMAMEM. To do this I have successfully used arm_dcache_delete(buff, size)...

@DD4WH - In the above GitHub link you reference this Forum thread https://forum.pjrc.com/threads/57267-Fast-Convolution-Filtering-with-Teensy-4-0-and-audio-board When I try to navigate to it I get an error message that says "Invalid Thread specified". I would like to read more about the...

Sorry, my misunderstanding @Mcu32. When you said "IRQ_SOFTWARE is used by the audio library " I thought you meant it was included in the imxrt.h file that is in the Audio Library. I didn't realize it was actually being used. Thanks for the clarification. I will use one of the IRQ_Reservedx...

Interesting. Do you @jmarsh know what it is used for in the Audio Library? I did get if working with IRQ_SOFTWARE (70) in a simple test I did. But it didn't use any of the Audio Library for this test. If the Audio Library uses one of the IRQ vectors, it would be good to know which one and for...

Thanks for the responses. It is probably easier for me to use one of the IRQ_Reservedx vectors. I didn't realize they were useable. Also, somehow I missed the IRQ_SOFTWARE (70) vector in imxrt.h probably because it is listed as RESERVED in the reference manual. Thanks again for the help. I...

I want to implement a simple software interrupt so I can initiate an ISR using a software command. Other microprocessors I have used have dedicated interrupt vectors for this purpose, but I could not find an IRQ_NUMBER_t in the i.MX RT1060 Processor Reference Manual or the imxrt.h. Has anyone...

Thanks @MarkT for your help in understanding this. And thanks @DD4WH for the sample IRs and your clarification on using minimum phase coefficients for low latency. Fun stuff!

Thanks for the quick response. I read up on the overlap methods and uniform-partitioned convolution and believe I understand the approaches. This helps a lot. A few questions more if you have time please: * You mentioned there wasn't enough uP horsepower to have all 128-block low latency...

I am trying to better understand the application of convolution in audio processing. I am well versed in DSP theory regarding Convolution, FFTs, IFFTs, Impulse response , FIR filtering etc. but haven't specifically used Convolution in audio processing. I am also very familiar with and have used...

I am trying to understand the algorithm used in to generate Band Limited Square Waves. Can someone point me to an article/url/forum post, or anything that would provide some explanation for this Audio Library function? Thanks

Moreover, I noticed in the comments that A10 & A11 (pins 24 & 25) shouldn't be used for audio, and A12 & A13 (pins 26 & 27) shouldn't be used for analogRead Sorry, I should have more specific on information source request. Where did you find the comments regarding the limitations of A10 -A13?

NJ-Tom, would you please point me to the data sheet you got this information from? Thx

A1: In my experience, the CS42488 reset line startup requirements are a bit sensitive. You need the CAT811T to make sure no short glitches occur during the power up process. If a glitch occurs, the CS42488 doesn't reset with a simple !RST pin toggle. When I tried holding !RST low with a Teensy 4...

I fixed this problem and thought I would document how. I found the following on page 1989 of the i.MT RT1060 Processor Manual. When I enabled things in the order outlined here, everything worked fine. If both the transmitter and receiver use the transmitter bit clock and frame sync: •...

I am trying to do single DMA SAI1 TDM input/output from a codec chip to a teensy 4. Each transfer is 8 - 32bit words. I am using code heavily leveraged from the Audio Library I2S and tdm code, but I am not using Audio streaming. My problem is that sometimes receiving ADC data works flawlessly...

For the example code above from @defragster, the double to int speed comparison was about 2x for multiply and 3x for divide. I modified the example to compare double to float. The result was that double multiply and divide both took 2x that of float. Also if you compare int to float looking at...

I have been measuring execution times using my logic analyzer and doing digitalWriteFast(pin, HIGH/LOW). Your 2x rule of thumb matches what I have been seeing. The T4/M7 is such a great device. I wish all the lower level details were easier to get find. I understand a manufacturer's need to...

It is probably somewhere in the Forum, but my searching was fruitless. What is the difference in machine cycles to do a single float/double multiply/divide for the T4.1? The data sheets says the T4 has double HW, but I can't find a reference that says how many instruction cycles each take. Any...

The 2.9ms is incorrect. If you are sampling at 44100 Hz and you take 256 samples, all the samples are real. And 256 samples cover 256/44100 sec = 5.8ms. You are correct however that the FFT output yields 128 frequency bins each with a real component and an imaginary component. The Audio Library...

Before answering your question about the need for a faster sampling rate, a few more details might help. At 44100 Hz sample rate and a 256 point FFT, the time window is about 5.8ms, not ~1ms. Also what do you mean by a 40 degree knock window at 6000rpm? What do you expect the spectrum to look...

Thanks @defragster for the previous post link. As I read the post, it leaves one with the impression that running at 600 MHz limits the Power On Hours to about 3 years. That is only the case if you are have a junction temperature of 95 degrees C and have it on continuously for the 3 years...

The effect of Junction Temperature on expected Product Lifetime is nicely documented here: https://www.nxp.com/docs/en/nxp/application-notes/AN12253.pdf Keep in mind if you look at the chart they are talking about POWER ON HOURS. In one of my heavy use applications I have the Teensy 4.1...

Maybe I am missing something. Using Serial.printf("%.2f°C\n", tempmonGetTemp()) to monitor the T4.1 I get Tjunction = 74degrees C. It is a pretty full application using two TDM interfaces, a TFT display and a few leds and pushbuttons. If I assume a very conservative 50 C/W that would mean...

I am using the Sparkfun ATP Carrier board for prototyping. The ATP Carrier schematic is here: Pin 13 (RTS1) and pin 15 (CTS1) are available on the ATP Carrier board connectors J23/24. My question is what Teensy 4.1 core pins do pins 13 and 15 correspond to?

I am using a MicroMod (MM) Teensy in a project. The MM schematic is here: Thanks to the KurtE spreadsheets, I understand which MM pins are equivalent to which Teensy 4.x pins. But the two pins labeled pin 13 (RTS1) and pin 15 (CTS1) on the MM connector aren't connected to the Teensy in the...

You may have already done this, but take a look at the schematic for the Sparkfun ATP Carrier Board they have to support a basic Micromod configuration. They have the USB_VIN connected to the MM and it comes from the USB connector. Here is the schematic link...

Wow! Thanks for solving my problem. Setting IM0 LOW like they did in the other focuslcds display you referenced got things working nicely. It is inconsistent with the table in the focuslcds data sheet for my display, but it works. So be it. Thanks again. Your tip was a lifesaver!

The display and driver chip are all in one unit.

Here is a link to the Digikey/Focuslcds data sheet https://focuslcds.com/content/E28RA-I-CW384-R_Spec.pdf

I purchased two LCD displays from Focuslcds via Digikey. They both have flex cables that interface directly to the display module, i.e., no backer PCB. One display has the ILI9488 control chip and works fine. The other has the ST7789V chip and it is not functioning properly. The SPI signals look...

Question for those more familiar with display drivers-Is there an 8bit parallel driver available somewhere that will work with the ST7789 control chip? If not, is it likely that one of the parallel libraries for the ILI9341 or ILI9448 would work without modifications?

ateter-I am also attempting to use SPI1 with the MM in my application. Besides moving the hardware lines to MM pins 67, 19, 8 17 and besides changing all the SPI references to SPI1 in the source library you were using, is there anything else you had to do in particular to get those pins in...

KurtE-The teensy 4.0 schematic shows the SD card DAT3/SD_B0_05 and the DAT2/SD_B0_04. I think your spreadsheet shows DAT3/SD_B0_04 and DAT2/SD_B0_05 with the names reversed? Not sure, but I thought I would point it out.

Rezo-Sorry, one more question. I have a touch screen in my application. If I am using the parallel interface DMA FlexIO2 (pin55) to the display, am I correct in assuming I can use the SPI(4) pins 57, 59 and 61 to communicate with a touch chip and that it would not interfere with parallel output...

Thanks for pointing that out. For this prototype I am laying things out so I can choose with jumpers to either run SPI of 8bit parallel. I see where you are setting the WR pin in FlexIO_Init(). I am not as FLEXIO savvy as I am sure you are, so I initially plan on using the same pin you...

Rezo-thanks for the information. I see that your parallel hookup is what I expected.

I am planning a custom PCB using MM, FPC and a bare display as well. Any chance you could share the portion of your schematic that shows the MM/parallel display/USB/USB host design? I am using the Sparkfun carrier PCB and the schematic that KurtE posted so far for the MM specific stuff. The...

Rezo, I am curious what hardware you are using to prototype this. Are you using one of the ILI948x displays with a flex cable (and adapter) to get to the displays parallel IO? Also, are you using the Teensy MM with a Sparkfun Carrier board or did you make your own carrier PCB similar to what...

Super useful. Thanks for the schematic information. I see that this uses an SPI interface to the display. I thought it was going to be using an 8bit parallel FLEXIO interface. Do you intend to try and do that with the micromod since it has the necessary FLEXIO pins visible?

KurtE-Really nice work! Any chance you'd be willing to share the schematic of your PCBway board? I'd like to do something similar for my application and it would save me some time. If you prefer not to share it, I understand. Thanks for all your Teensy contributions. They have helped me...

Does anyone have a part number for a SD card connector that will fit the Teensy 4.0 pad pattern?

Good suggestions. I am not a big fan of POGO connections, but I will take a closer look at the SPI SD route. Thanks