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  • brtaylor's Avatar
    02-22-2019, 05:14 PM
    I think it's interesting the reference manual mentions NAND and EMMC. One big item that's been on my wish list for the Teensy 3.x is availability of large amounts of non-volatile memory. Has anyone looked into it yet?
    1849 replies | 48411 view(s)
  • brtaylor's Avatar
    02-22-2019, 01:52 AM
    Some notes regarding analog - this seems like it's defined in analog.c, static const uint8_t pin2sc1a, which is an array where the index is the pin number and the stored value refers to the ADC channel number. For...
    50 replies | 2290 view(s)
  • brtaylor's Avatar
    02-20-2019, 07:16 PM
    Thanks! I kind of like this approach - seems like it could be lower noise than my original idea.
    3 replies | 78 view(s)
  • brtaylor's Avatar
    02-20-2019, 05:46 PM
    When you call pinMode, portConfigRegister is called, which is defined in pins_arduino.h. This is simply calling digital_pin_bitband_and_config_table_struct digital_pin_to_info_PGM from pins_teensy.c with the index of...
    50 replies | 2290 view(s)
  • brtaylor's Avatar
    02-20-2019, 06:54 AM
    Huh, I haven't been able to duplicate the freezing yet, but I think you would need to configure the pins in pins_teensy.c around line 106.
    50 replies | 2290 view(s)
  • brtaylor's Avatar
    02-20-2019, 02:21 AM
    Overview: I'm working on a Teensy 3.6 project where I would like to create an analog signal conditioning circuit that can be flexibly configured by the Teensy to work with a variety of input signals. I'm anticipating...
    3 replies | 78 view(s)
  • brtaylor's Avatar
    02-18-2019, 02:06 AM
    Thanks Mike, For the MPU9250 library, did you try both SPI and I2C? I just tried it with I2C and I'm not getting communication with Wire (I2C1, pins 18/19) and Wire3 (pins 16/17) is undefined. EDIT: nevermind, pins...
    1849 replies | 48411 view(s)
  • brtaylor's Avatar
    02-18-2019, 01:53 AM
    Eigen (https://github.com/bolderflight/Eigen) seems to work on Teensy4.
    1849 replies | 48411 view(s)
  • brtaylor's Avatar
    02-14-2019, 06:58 PM
    Super easy software fix - just needed to initialize the internal regulator during startup. I'll get a modified core library available shortly. EDIT: Modified core library available here:...
    48 replies | 10931 view(s)
  • brtaylor's Avatar
    02-14-2019, 05:20 PM
    I dug into this more this morning. If I apply regulated 3.3V power to VIN, the board works. This board was designed to rely on the internal regulator in the MK66 microcontroller; however, the Teensy 3.6 does not use...
    48 replies | 10931 view(s)
  • brtaylor's Avatar
    02-14-2019, 12:35 AM
    Not OP, but thanks for the code and link, I'm tackling a data logging project currently. FWIW, my test results for a SanDisk Extreme Plus card are: SdFatSdioEX write benchmark SdFatSdioEx uses extended multi-block...
    6 replies | 243 view(s)
  • brtaylor's Avatar
    02-08-2019, 04:57 AM
    brtaylor replied to a thread SPI Slave in Project Guidance
    Oh wow, TSPISlave looks exactly like what I want. Going to give that a try, cheers!
    10 replies | 162 view(s)
  • brtaylor's Avatar
    02-08-2019, 01:14 AM
    brtaylor started a thread SPI Slave in Project Guidance
    I'm trying to transfer data very quickly between 2 Teensy 3.6's. I'm trying to use SPI, since that should be the fastest method. I'm using the following config for my SPI master Teensy 3.6: * CS: 10 * MOSI: 11 *...
    10 replies | 162 view(s)
  • brtaylor's Avatar
    02-07-2019, 04:24 PM
    brtaylor replied to a thread uNav INS in General Discussion
    Yes, NED. I can recommend Dan Simon's book for EKF. There are a few papers that mention the EKF presented here at a high level, but none (to my knowledge) go into the specifics. It's a very straightforward filter,...
    674 replies | 117463 view(s)
  • brtaylor's Avatar
    02-07-2019, 06:35 AM
    brtaylor replied to a thread uNav INS in General Discussion
    Hi Bruce, sorry I've been down with an upper respiratory bug for the past few weeks. And now I'm playing catch up. I haven't had a chance to track down exactly what I was experimenting with. The MPU9250 library I...
    674 replies | 117463 view(s)
  • brtaylor's Avatar
    02-06-2019, 11:53 PM
    There are arduino cores for STM32, but it really depends on the exact version. For example, this supports a few of the STM32s: https://github.com/GrumpyOldPizza/arduino-STM32L4 Also:...
    10 replies | 221 view(s)
  • brtaylor's Avatar
    02-03-2019, 04:12 PM
    Not yet. I've had limited time to debug it and my current scope is pretty terrible. I may manufacture one soon with a slightly different crystal, see if that fixes the issues.
    48 replies | 10931 view(s)
  • brtaylor's Avatar
    02-01-2019, 10:51 PM
    brtaylor replied to a thread uNav AHRS in General Discussion
    Honestly, for heading and tilt in walking conditions the AHRS might not be appropriate - I'm not sure you would see enough dynamic motion in that context. I would consider implementing a tilt-compass, which is what...
    920 replies | 121827 view(s)
  • brtaylor's Avatar
    01-31-2019, 11:42 PM
    No, this is a pretty oft asked subject. I suggest searching the forums for similar questions regarding updating firmware over different protocols. The only supported method is via USB and any other approach will require...
    3 replies | 120 view(s)
  • brtaylor's Avatar
    01-21-2019, 08:48 PM
    One final suggestion - if you are going to be doing floating point math on the second Teensy, give the 3.6 a look. It has a hardware FPU and can give you very fast calculations if you remember to use the float version...
    5 replies | 163 view(s)
  • brtaylor's Avatar
    01-21-2019, 07:03 PM
    If wire lengths between the two Teensys are small, my preference would be I2C with the Teensy reading the ADC's set up as I2C Master. You could transfer up to 101 kBytes/s if you overclock your Teensy 3.2's to 120MHz:...
    5 replies | 163 view(s)
  • brtaylor's Avatar
    01-20-2019, 06:16 PM
    Read this thread, it discusses an ADC library for Teensy that enables synchronous sampling of both channels: https://forum.pjrc.com/threads/25532-ADC-library-update-now-with-support-for-Teensy-3-1?highlight=pevide+adc...
    5 replies | 163 view(s)
  • brtaylor's Avatar
    01-19-2019, 04:15 AM
    I'm working on debugging this hardware design. Two boards have been manufactured with the same symptoms: 1. The bootloader shows up correctly when plugged into USB 2. The teensy loader loads the program and reboots,...
    48 replies | 10931 view(s)
  • brtaylor's Avatar
    01-16-2019, 10:42 PM
    So, theoretically speaking, if we run Teensy 3.6 at 240 MHz, we can compute that a single tick would be 4.1667 ns. If we used the newest overclocking scheme, which can get us to 256 MHz, that drops to 3.9 ns per tick. ...
    19 replies | 634 view(s)
  • brtaylor's Avatar
    01-16-2019, 07:08 PM
    You should be able to get the timer working - IIRC, using the Teensy 3.6 clock and counting cycles will get you 4 ns precision at 240 MHz. I've thought about creating a nanos() library, similar in functionality to...
    19 replies | 634 view(s)
  • brtaylor's Avatar
    01-14-2019, 06:28 AM
    Roughly in the $40's or $50's.
    6 replies | 267 view(s)
  • brtaylor's Avatar
    01-14-2019, 06:28 AM
    I think the approach is to extend the pin numbering (https://forum.pjrc.com/threads/54114-Extended-Pin-Numbering), with a forked Teensy core, and then let the community add support for various ports and libraries from...
    6 replies | 267 view(s)
  • brtaylor's Avatar
    01-14-2019, 12:47 AM
    Neat project! Regarding the Teensy 3.6 "Pro", see this: https://forum.pjrc.com/threads/53225-Teensy-3-6-quot-Pro-quot-Feedback I've got some initial boards and am in the process of debugging. Not sure how long it...
    6 replies | 267 view(s)
  • brtaylor's Avatar
    01-13-2019, 03:06 PM
    brtaylor replied to a thread uNav INS in General Discussion
    Mike asked a similar question and the honest answer is I don't remember, but should be working with it again soonish and find out why: https://github.com/bolderflight/uNavINS/issues/3 I would guess that you should...
    674 replies | 117463 view(s)
  • brtaylor's Avatar
    01-10-2019, 08:05 PM
    That's why you need the size as a function parameter as well. Consider memcpy, which is: memcpy(void *dest, void *src, size_t size) In your case, JarkkoL recommended: void EBYTE::SendData(const void *data_,...
    6 replies | 225 view(s)
  • brtaylor's Avatar
    01-04-2019, 06:49 PM
    The magnetometer will not show up on an I2C scan unless you specifically set the MPU-9250 into bypass mode (register 55, bit 1). Edit: mis-read post, looks like you have it in bypass mode to pick it up at 400 kHz....
    1849 replies | 48411 view(s)
  • brtaylor's Avatar
    01-02-2019, 11:16 PM
    Often I use analogWrite rather than the servo library. Noticed that the servo library would issue commands round robin, which old receivers would also do, but means a lot more delay if you are using lots of servos....
    1849 replies | 48411 view(s)
  • brtaylor's Avatar
    01-02-2019, 08:15 PM
    To me, I think the focus should be on users getting expected behaviour rather than performance. I think this is doubly important with Arduino users, who may not be digging into compiler flags. There are use cases where...
    1849 replies | 48411 view(s)
  • brtaylor's Avatar
    01-02-2019, 07:35 PM
    As far as I'm aware, there is not a good suffix to add to specify a double, only 'f' to specify a float. So, it seems to me like constants that are not specified would need to be treated as doubles on Teensy 4.0 rather...
    1849 replies | 48411 view(s)
  • brtaylor's Avatar
    01-02-2019, 06:08 PM
    brtaylor replied to a thread uNav INS in General Discussion
    Long term, yes, I would like to incorporate air data into the INS estimate when available. I'm not sure what the effect would be on output accuracy, but, it would help arrest drift in cases where GPS is unavailable for...
    674 replies | 117463 view(s)
  • brtaylor's Avatar
    01-01-2019, 10:00 PM
    The servo shouldn't have feedback over the signal line - I use a 3.3V signal to drive servos and power them anywhere from 5V to over 7.2V (high voltage servos) just fine with a Teensy 3.6.
    1849 replies | 48411 view(s)
  • brtaylor's Avatar
    01-01-2019, 09:55 PM
    Awesome!! One small nit - it's Bolder Flight Systems rather than Boulder Flight Systems :)
    6 replies | 1759 view(s)
  • brtaylor's Avatar
    01-01-2019, 09:53 PM
    50 Hz is still the "standard" for servos.
    1849 replies | 48411 view(s)
  • brtaylor's Avatar
    12-30-2018, 05:36 PM
    The cool thing is that nanopb is protobuffers. So I'll use nanopb on Teensy 3.6, regular protobuf on a BeagleBone Black or a desktop (which can transpile to C++ code, Node.js, Rust, etc). It all works together. You can...
    5 replies | 225 view(s)
  • brtaylor's Avatar
    12-26-2018, 11:39 PM
    brtaylor replied to a thread uNav INS in General Discussion
    Mike is the KF the 15 state INS or the Euler AHRS?
    674 replies | 117463 view(s)
  • brtaylor's Avatar
    12-26-2018, 11:35 PM
    brtaylor replied to a thread uBlox Library in General Discussion
    Not yet, but it's on my long term "to do" list. My goal is to incorporate it by overloading the class declaration, like: * Serial: UBLOX ubx(Serial1, 115200); * I2C: UBLOX ubx(Wire, 0x48); The rest of the methods...
    75 replies | 12506 view(s)
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