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Type: Posts; User: Bill Greiman

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    If you get an error print please add these...

    If you get an error print please add these additional changes.

    In SDTest.ino add this routine:


    void dbgSdError() {
    if (SD.sdErrorCode()) {
    SD.errorPrint(&Serial);
    while (true) {}...
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    I downloaded the above files. I don't have the...

    I downloaded the above files. I don't have the WIZ850IO so I disabled the section, from about line 83 - 98 of SDTest.ino and change the SD CS for the T4 breakout.

    I ran SD.h for about 300 files...
  3. Happiness - New Cable Fixed Problem

    New cables arrived from Digi-Key. I put the T4 on stacking headers to avoid the kink.

    17557

    Tried Paul's SD.h on SDIO and it worked.


    Initializing SD card...Wiring is correct and a card is...
  4. FFC-8P to 2.54 Through Hole

    I ordered these FFC adapters.

    https://www.amazon.com/SUKRAGRAHA-Connector-Adapter-2-54mm-Through/dp/B07T7FCBVS

    It would be great if Paul would sell a T4 with the FFC connector.

    A little...
  5. My cable had an almost 90 degree sharp bend in...

    My cable had an almost 90 degree sharp bend in the blue stiffener right at the connector. I ordered lots of cables so I will try to do a gentle bend and keep the Pogo pins.

    The new SdFat-beta...
  6. I think I see the problem. Its the cable. The...

    I think I see the problem. Its the cable. The kink in the cable cracked the foil. The kink was extreme and in the blue stiffener.

    When I removed the T4 and pinched the cable flat, the ends of...
  7. I see this is a known problem. ...

    I see this is a known problem.

    https://forum.pjrc.com/threads/54711-Teensy-4-0-First-Beta-Test?p=211858&viewfull=1#post211858

    You can't plug the T4 into it's socket without a bend in the stiff...
  8. I am using the the SDIO socket to develop an fast...

    I am using the the SDIO socket to develop an fast SDIO driver for SdFat.

    This socket works intermittently when I remove the T4 from its connector and pinch the FFC ribbon cable's blue area...
  9. T4 Unreliable Connection with Breakout SD Socket

    I have been using a Teensy 4.0 beta-2 on a breakout board Paul sent. I am using it for development of SdFat.

    Initially the connection to the SD seemed OK. When the breakout arrived, I checked the...
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    Looks like there is no way to correctly mux the...

    Looks like there is no way to correctly mux the SPI pins to the SD socket. It is nice that Teensy 3.5/3.6 allows this.

    SPI access is nice since you can insure the max latency for a write is small...
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    SPI2 and micro SD

    Just received my T4B2. Tried the microSD socket with SD.h and it works with several examples.

    I see that the microSD socket is connected to both SPI2 and the uSDHC controller.

    I decided to...
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    Uhs-i sd

    I assume UHS-I SD cards will be supported. About a year ago I bought a STM32H7 400 MHz Nucleo board with UHS-I 208 MHz support.

    It's really difficult to get even fair DMA performance. UHS-I...
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    Yikes! This is most of high performance...

    Yikes! This is most of high performance computing.

    I started this thread with the misunderstanding that the EventResponder ruled out use of exception vectors for use by an RTOS.

    I understand...
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    I have a better answer to Frank's question. I...

    I have a better answer to Frank's question.

    I have ported the new FreeRTOS V9 to three Arduino architectures. As I expected, FreeRTOS is best as a scheduler so it is not worth mods to the Arduino...
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    Start with this...

    Start with this, then this, and, this.

    Search for "when to use a rtos" with google. Use of an RTOS in embedded systems is very controversial so read several pro and con articles.

    Here is a...
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    Yes I overwrite the vectors. I was trying to say...

    Yes I overwrite the vectors. I was trying to say EventResponder is disabled so you can't use it to solve the problem of making the call look synchronous to the thread by using this call.


    bool...
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    I will describe what needs to happen for an SPI...

    I will describe what needs to happen for an SPI DMA transfer.


    If the SPI call is:


    SPI.transfer(txBuffer, rxBuffer, count);

    When the DMA transfer starts, transfer() must wait on a...
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    Support for FreeRTOS

    I was planning to drop support for my FreeRTOS library. I didn't realize how many people were using my old port. I should have known by looking at GitHub traffic.

    Since there are so many users, I...
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    The answer to what users want in an RTOS is...

    The answer to what users want in an RTOS is simple, FreeRTOS if they can't use Linux. I like other RTOSs much more but I keep getting mail asking me to update my port of FreeRTOS.

    2017 Embedded...
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    I posted an example that replied to your...

    I posted an example that replied to your conjecture that beginners couldn't deal with an RTOS. Did you look at it? It's a real example with real code, not rhetoric.

    Sorry, I should have not...
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    The reason it is no longer used is that the cost...

    The reason it is no longer used is that the cost of developing big systems is now in software. Big systems like LHC use thousands of micro-controllers. There is no longer a place for a clever trick...
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    Beginners have no problems with setting stack...

    Beginners have no problems with setting stack sizes.

    I patched my ChRt library so it will run on Teensy 3.6. This example illustrates how to set stack sizes.

    Here is output:


    The unused...
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    The idea of using an interrupt controller has...

    The idea of using an interrupt controller has been used before in place of an RTOS. You are just 50 years too late to get credit for the idea.

    The first I know of were early NASA flight control...
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    First, a thread is activated when it is the...

    First, a thread is activated when it is the highest priority thread and runable. Threads are not runable while they wait for events. Threads wait on mutexes, semaphores, sleeping for an interval or...
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    The first point, "System code is not thread...

    The first point, "System code is not thread safe". A key function of an RTOS is to handle this.

    I am a bit puzzled, I noticed TeensyThreads has a "Mutex" but it appears to not queue waiting...
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    Wow, Nominal Animal, great insight. There are so...

    Wow, Nominal Animal, great insight. There are so many points here but I will only reply to a few that I think are most important.

    First, the system should start as Arduino and look like Arduino...
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    I have been using the STM32 Cortex-M7 chip for...

    I have been using the STM32 Cortex-M7 chip for almost two years, it was announced mid 2015. It is more than twice as fast as an M4 chip running at the same clock frequency. In a few days I should...
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    No, commandeering interrupts is not the problem. ...

    No, commandeering interrupts is not the problem. This change made me realize that it is not worth porting an RTOS when you get almost none of the new functionality.

    As I said above, the path of...
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    The problems of taking full advantage of a modern...

    The problems of taking full advantage of a modern RTOS in the Arduino environment with new Cortex M7 and multi-processor chips are overwhelming. It's no longer about a scheduler. You need a whole...
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    I assume the same is true for PendSV. void...

    I assume the same is true for PendSV.


    void pendablesrvreq_isr(void)
    {
    EventResponder::runFromInterrupt();
    }

    It's probably time to give-up trying to support an RTOS on Arduino style...
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    RTOS no longer usable with Teensy?

    Looks like EventResponder prevents use of FreeRTOS, ChibiOS and other RTOSs.



    Should I remove Teensy support from ChibiOS/RT, FreeRTOS, and NillRTOS on GitHub?

    I don't see any weak hook or...
  32. Section 5.2.1 Figure 18 shows clock high when...

    Section 5.2.1 Figure 18 shows clock high when idle and clocking data on rising clock. That suggests mode 3. Many sensor chips will work in mode 0 or 3 (corrected from mode 1 or 3).

    It depends on...
  33. The FXOS8700 and FXAS21002 get good reviews but...

    The FXOS8700 and FXAS21002 get good reviews but you will still need to use DRDY with the Gyro. Gyros are have a vibrating element and I believe the readout sensors are synchronized with the...
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    Have you deactivated the ILI9341 by setting its...

    Have you deactivated the ILI9341 by setting its chip select high?


    // before access to SD
    pinMode(ILI9341_CSPIN, OUTPUT);
    digitalWrite(ILI9341_CSPIN, HIGH);
  35. I found my L3GD20H Adafruit gyro break-out board...

    I found my L3GD20H Adafruit gyro break-out board and did some tests. Kalman filtering looks like a good idea.

    I mounted the L3GD20H on big block of wood and ran it at several data rates to see...
  36. The data sheet indicates that setting CTRL1 to...

    The data sheet indicates that setting CTRL1 to 400 MHZ is really approximately 378.8 Hz. The footnote suggests that the range can vary from about 314 Hz to 438 Hz.

    I am assuming the "400 Hz"...
  37. Have you read the Datasheet...

    Have you read the Datasheet for the L3GD20H? Seems like the actual ODRs are not neat values like 400 Hz. In Table 3 in Section 2.1, the rates are.



    There is a footnote that is very disturbing....
  38. I think I have a L3GD20H breakout board. Do you...

    I think I have a L3GD20H breakout board. Do you just want to log values each time a new set of data is ready?

    Could give more details how you are using the L3GD20H?

    Did you write the L3GD20H...
  39. At 400 Hz, the time to write the SD should not be...

    At 400 Hz, the time to write the SD should not be a problem if you are using a Teensy 3.6.

    Which gyroscope are you using? How long does it take to read the three values?

    The ExFatLogger...
  40. maxLogMicros is the time to read sensors and does...

    maxLogMicros is the time to read sensors and does not depend on the SD card.

    maxWriteMicros is the time to write one 512 byte sector to the card. About 140 Ás is required for the SPI transfer...
  41. 16 Ás is the time to read the ADC values. It took...

    16 Ás is the time to read the ADC values. It took 16 Ás to execute the for loop in this function.


    void logRecord(data_t* data, uint16_t overrun) {
    if (overrun) {
    // Add one since this...
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    The readWrite example does not support the Teensy...

    The readWrite example does not support the Teensy 3.6 built-in uSD. You must use either the SdFatSdio or SdFatSdioEX class.

    Only the bench.ino, SdFormatter.ino, SdInfo.ino, and TeensySdioDemo.ino...
  43. I posted the version of SdFs with two...

    I posted the version of SdFs with two optimizations for FAT16/FAT32 pre-allocated files.

    The first avoids access to the FAT table when a file is known to be contiguous.

    The second adds a...
  44. I decided to try optimizing FAT16/FAT32 for...

    I decided to try optimizing FAT16/FAT32 for contiguous files. I realized that I had done most of the work with exFAT.

    After more tests, I will post it to GitHub.

    Here is the difference for the...
  45. I added FsFile::preAllocate(). I also...

    I added FsFile::preAllocate().


    I also corrected a few errors in the documentation and defined symbols for file system types.
  46. Try the TeensyRtcTimestamp.ino...

    Try the TeensyRtcTimestamp.ino example. I ran it with exFAT and this was the output.


    Type any character to begin
    DateTime::now 2017-08-30 12:41:44
    2017-08-30 12:41 35 RtcTest.txt...
  47. pre-allocation only works well on FAT32 if you...

    pre-allocation only works well on FAT32 if you maintain a fake valid length and a local indication the file is contiguous. I think FatFS may do that but only partially. There are problems with this...
  48. I did a number of tests on Windows 10. If you...

    I did a number of tests on Windows 10. If you scan a volume for errors that has a files with large pre-allocations, there is no error or repair. It will work fine on SdFs, validDataLength and...
  49. Most manufacturers have stopped maintaining this...

    Most manufacturers have stopped maintaining this field. Also the Version number has been 8.0 on SanDisk cards for a long time.
  50. I have not decided how to handle features like...

    I have not decided how to handle features like preAllocate where the FAT16/FAT32 version is totally different than the exFAT version.

    Here is the FAT version:


    It's not too useful since there...
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