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  • mborgerson's Avatar
    06-27-2020, 05:16 PM
    I haven't worked with external card readers on the T4.0. I got out my binocular microscope, finest tweezers and soldering tip and coerced a micro-sd card socket to bond with the misfit pads on the bottom of the T4.0. ...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    06-27-2020, 02:31 AM
    Here is a link to the MTP library I am using. I haven't posted it before because you have to edit some of the core USB libraries to get it to work. If you've gone through that before, you should be able to get a USB...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    06-26-2020, 09:58 PM
    I've attached a zip file with the latest incarnation of the generic data logger. It has been updated to allow the use of more than one logger object in a program. I have added an example that uses a slow and a...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    06-25-2020, 05:07 PM
    With some simple mods to the generic logger, I am now able to use two logger objects to save data to two different files at different collection rates. Apparently, SDFat 2.0B has no problems having two files open for...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    06-24-2020, 08:00 PM
    Your comment that some applications really don't fit the timer-based buffering and storage model is spot on. The GPS logger is really a bit of a stretch. It might be be better done by increasing the size of the...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    06-24-2020, 03:13 PM
    I've considered the possibility of event-triggered logging, and I think it could be implemented with a modification of the solar logger example. For event-triggered logging, the attached binary writer would examine the...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    06-24-2020, 03:02 AM
    Sorry about the delay in response to questions---but I was on a camping trip where I tested a version of the data logger software to collect GPS data. GPS collection is a bit of a PITA in that you get a swarm of NMEA...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    06-04-2020, 11:00 PM
    I suggest that you be very cautious when you try to run multiple devices at high speeds on the same SCK line. The capacitive loading of many connected devices has caused problems for other users.
    1 replies | 72 view(s)
  • mborgerson's Avatar
    05-30-2020, 03:14 AM
    This afternoon I did some tests in a common data logger configuration: * Logger is powered by an external power supply. * The trace on the bottom of the Teensy that connects USB 5V to VIN is cut. When the USB...
    320 replies | 39982 view(s)
  • mborgerson's Avatar
    05-29-2020, 06:10 PM
    Buried in the code for the base FSFile type is the following: /** The parenthesis operator. * * \return true if a file is open. */ operator bool() {return isOpen();}
    320 replies | 39982 view(s)
  • mborgerson's Avatar
    05-28-2020, 08:56 PM
    I have taken the first steps toward integrating the MTP responder into my generic data logger application. One thing that was apparent early on was that having the data logger and the MTP responder each having their...
    320 replies | 39982 view(s)
  • mborgerson's Avatar
    05-26-2020, 09:40 PM
    I am using SDFat 2.0b. I installed the latest version today---which still wants to include Time.h somewhere in the Fcntl.h chain. Fcntl.h is used by default in SDIOConfig.h in SDFat 2.0b on ARM chips. At this...
    3 replies | 131 view(s)
  • mborgerson's Avatar
    05-26-2020, 07:36 PM
    These warnings started popping up in my generic data logger code after the install of Teenysduino 1.52. I finally tracked down the source of these warnings to the fact that SDFat 2.0b includes the fcntl.h header when...
    3 replies | 131 view(s)
  • mborgerson's Avatar
    05-18-2020, 10:43 PM
    I note that all the errors shown post #37 above occur when the buffer pointer is ~0x70E12400. I think this is in the memory range occupied by the 2nd PSRAM, which is soldered onto pads normally occupied by an SPI...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-18-2020, 10:15 PM
    The problem with all these proposals are some things I hadn't yet considered: 1. Many speakers that have adequate output at 500 to 2500Hz are an inch or two in diameter. The resulting audio output may have some...
    17 replies | 442 view(s)
  • mborgerson's Avatar
    05-18-2020, 09:55 PM
    Hmm, if the issue is something happening at interrupt time, then increasing the IntervalTimer priority might have an effect. I think I will also investigate the code for reading the elapsedMillis() and...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-18-2020, 09:45 PM
    Errors that pop up just a few times in millions of records are hardest to troubleshoot. I can think of several reasons that things like this might happen: * Something strange in interrupt land that makes the...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-18-2020, 06:52 PM
    Another thought just occurred to me: How does the PSRAM handle storage of 33-byte structures? Is there some mechanism unknown to me that doesn't cope well with odd-sized writes?
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-18-2020, 06:05 PM
    Thanks for the notes. 1. I'll definitely check for proper spelling of file names. Windows HAS made me a bit lazy in that respect. 2. A 33-byte packed structure??? I've always avoided structures with odd...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-17-2020, 12:31 AM
    This update to the data logger has the following changes: 1. Used method proposed by @defragster to avoid blocking interrupts on every call to CheckLogger. 2. Added code which checks free space on the SD card and...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-16-2020, 06:20 PM
    On the subject of SD Cards: Five to 10 years ago, I used a lot of SanDisk cards with good results. Then about five years ago SanDisk cards started getting counterfeited on a large scale. A co-worker at Oregon...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-16-2020, 05:28 PM
    I'll work over these issues today: 1. type casts to make sure the buffer needed calculation is done with uint64_t internally. 2. Investigate ways to handle "disk Full" situations. The logger really shouldn't...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-16-2020, 04:43 AM
    Here is an update library source and some new examples that illustrate file playback. One program is designed to log timing data very quickly on a T4.1, then verify that no records were skipped during logging. The...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-16-2020, 03:19 AM
    Xfer and defragster: I took your comments to heart and made the following changes: 1. The internal calculations for the buffer size now use a uint64_t and check for values out of the uint32_t range. 2. I added a...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-15-2020, 04:16 PM
    The calculation of bufferneeded does need some work. Your example of: bufferneeded = ((structsize * collectionrate ) / 1000) * mSecLen; Is OK for very fast collection, but will return zero for a 4-byte...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-15-2020, 03:57 PM
    I'll be trying out some of the T4.1 tests later today. I got the headers and PSRAM chip soldered on yesterday, so the hardware is ready to go. I agree that there should be some way to verify files besides plugging...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-14-2020, 09:35 PM
    The DataLogger class provides the collection, buffering and storage elements for a generic data logging application. It has the following characteristics: * A user-defined storage structure allows many different...
    86 replies | 1837 view(s)
  • mborgerson's Avatar
    05-13-2020, 05:38 PM
    I just caught on to the fact that you want to measure the distance between the microphone and the speaker. That's somewhat easier than the problem I was working on: measuring the distance from the mic/speaker and a...
    17 replies | 442 view(s)
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About mborgerson

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About mborgerson
Biography:
building embedded systems for oceanographers since 1978
Location:
Corvallis, OR
Interests:
travel
Occupation:
Retired embedded systems engineer

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