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Thanks for the suggestions! I think I'll try a completely separate regulator for the SD card. It seems like this noise doesn't have much of an effect on the ADC, since when I short the inputs to the ADC channels and perform sampling, the noise measurement adheres to the spec quite nicely. It's...

I have a data logger which uses Teensy 3.2 to fetch data from the ADS1298 ADC and store it on an SD card. I'm also using the 3.3V output of the LDO on the Teensy board to provide power to a miniature 9723GX Sonion microphone. The output of the microphone is sampled by the ADC at 1 KS/s. The...

It's hard to tell what the problem is without further details... Which GUI are you using? What firmware do you have running on Teensy? Is is matlab that's decoding the sample values or the Teensy?

Got extremely busy with another project, thus couldn't dedicate much time to this, but here's the very preliminary ADS129x library if anyone's interested. Hopefully I'll get back to it in the next few weeks.

Indeed GPS would be ideal, but I need the device to consume as little power as possible to achieve battery life of 5-8 hours off a 100 mAh LiPo battery. Also it needs to be small - matchbox size and finally in the majority of cases it will operate indoors. Excellent, I'll try it! If the...

Ok will do, thanks a lot!

Thanks for the suggestion, seems to me that this should work. So considering Teensy's RTC hardware, what do you think would be a reasonable time window within which the devices' RTCs stay within few seconds of each other after being synced with a chronodot?

Yes I understand that they will drift. All of the devices will operate in the same room and otherwise in very similar conditions. We'd want them to by in sync for 2 to 8 hours and the acceptable difference would be less than 3 seconds, ideally 1 second. At the moment they don't, any suggestions...

No they are not connected to each other, that's why I need their RTCs to be set form the same master clock (programming computer's clock).

I need to synchronise RTCs of multiple Teensies without a wireless module or GPS. I thought it should be possible to do by transferring the programming computer's current time to the RTC when the sketch is uploaded. Is that feasible? If yes, how would one go about doing that? If not, are there...

Well it all depends what you'd like to do with the ADC... I use START to start/stop the conversion, it can be tied HIGH to keep the converter running continuously, but to conserve power I don't do it. I power down the ADC by pulling PWDN low when the system is waiting for the button press while...

I wish I could... The cards with low power consumption and interoperability with other SPI devices on the same bus are hard to come by.

So I've tested the new "faster" code just now and it runs fast when not returning the value read, but as soon as I put the return statement in, it is as slow as the original one... So unless the return statement is somehow not required there's no improvement. But then based on your explanation...

I don't have the hardware in front of me at the moment, but I've noticed, that in the faster version of the code the r is never returned by the transfer function, so I was wondering if that's the reason why that code runs faster, since once again the value fetched isn't used? But then it doesn't...

Thanks for the info! I'll try it out.

Great, thanks a lot! And once more, sorry for the time wasted... Did you have to look at assembler to figure this out, and are there any particular tools that I could use to try and figure it out myself next time around or is it primarily experience?:)

Yes, indeed, I knew that it doesn't have anything to do with the ADC itself, so I should have simplified the test case, sorry.

I've rechecked the schematic against the code, it all looks good to me. I've also checked my PDF against this document (http://www.ti.com/lit/ug/sbau171c/sbau171c.pdf) it look fine as well.

Sure, I'll double check it first thing tomorrow. I'm 8 hours in front, so will let you know before you get to it tomorrow.

Yes it can be a bit tricky to connect it up. The diagram looks good to me, it's a bit hard to check the soldering with just the picture, but I can see there is a ground plane on one of the sides of your breadboard, that could be the area to check for potential shorts. I can see you've added some...

Hi Paul, any news on the test?

There are plenty of threads discussing the question of logging data to the SD cards, here's one of the recent: http://forum.pjrc.com/threads/26210-Teensy-3-1-MS5637-Pressure-Sensor-Data-Logging-SD-Card-Latency You could also check Bill Greiman's fastLogger for ideas on how to do this...

Ah:)Glad it works now, don't worry, happens;)

Well if you installed all the software correctly and since you don't see it in the available devices list it seems to me that something's wrong with your board, a usb cable or your usb port. Try plugging it into a different usb port and if that doesn't work try using a different usb cable. If...

I presume you've installed Teensyduino from here https://www.pjrc.com/teensy/td_119/teensyduino.dmg and used the latest Arduino.app http://arduino.googlecode.com/files/arduino-1.0.5-macosx.zip?

In Arduino IDE, do you see Teensy in the list of available serial devices, i.e. in Tools->Serial Port you should see entries like /dev/tty.usbmodem341261.

I would imagine it should work in much the same way as any other Teensy. So when you press the button do you see any activity in the teensy loader window, i.e. does it change to Programming... (with a progress bar) and then to Reboot OK?

Yes I know and remember that I've promised the library for the ADC. I haven't posted it yet, because I think it needs more work to be useful to most people. In any case it's included in the ZIP attached and I'd appreciate any comments you might have with regards to it. Here's the ZIP file with...

Paul, I know this is not related to your current work on SPI library, but would you be willing to try it out? I could zip all the relevant libraries together with the ADC wiring schematic and send it over.

Yes I'm aware of that and it's great, but unfortunately when it comes to the SD cards all sorts of things happen (those things are just nightmare to work with). At the moment my hardware SPI, with both ADC and SD card on it, works for SanDisk cards...

I'm interfacing Teensy with an external 4-channel 24-bit ADC and saving data to the SD card. The SD cards I currently have don't work with other SPI devices placed on the same bus. While waiting for the delivery of other SD cards I've implemented a software SPI which is used by the ADC, while...

Yes I'll share the code as soon as I have it fully tested.

Paul, so I've written the test for my setup over the weekend and it seems to work no problem so far it seems like my original issues were the result of the SD cards behaving in a very strange way (as described here: http://forum.pjrc.com/threads/26242-Teensy-3-1-SD-card-test-request). I will be...

Kurt, just to confirm that it's exactly the same behaviour as I observe would you mind running the same code once again but this time substituting the line with SPI.transfer(0X15); with SPI.transfer(0XFF); and posting your results? Valentin

Just wanted to update you all on my ordeal with the weird behaviour of my SD cards. This I believe is relevant for anyone trying to put an SD card with another device on the same hardware SPI bus and trying to access that other device in between writes to a contiguous file on the SD card. So I...

Great! I hope to have it done tomorrow, if not - Monday.

Tried it with both the official SDFormatter and the sketch, still the same. I just can't get my head around for why it would work fine with SPI.transfer(0XFF); and won't work with SPI.transfer(0X15); seems pretty arbitrary to me...

It's essentially impossible to figure out what might be wrong from the description alone. It's most likely a bad connection (maybe a tiny solder bridge?). Another possibility is that you've blown something up... Measure the overall current draw of both circuits and compare. High res photos of...

With ADS129x whenever the new data is ready DRDY pin is asserted low, thus my plan was to attach interrupt to that pin and in this way fetch the data from the ADC storing it in the buffer. After 512 bytes are read they are to be sent to the SD card in the main program. So I think scenario #2 is...

Have you ordered the adaptor for it as well or do you have other means of connecting the TQFP-64 to Teensy?

Checked it multiple times... Even tried soldering to the pins instead of using the breadboard, just in case. The strangest part is that code runs fine if I substitute line SPI.transfer(0X15); for SPI.transfer(0XFF); or SPI.transfer(0XFE);... So depending on the byte I send before writing to the...

Wow, Paul, sounds great, I'll get to work! Thanks!

Thanks a lot! Well that's very weird... It works for everyone except for us here. This is what I get when I run this sketch: Type any character to start Free RAM: 57279 Start raw write of 5120000 bytes at 51200 bytes per second Please wait 100 seconds error: writeData failed SD errorCode...

Could someone with a Teensy 3.1, SD shield and an SD card run the following sketch and reply with the results? I've got mixed reports from 3 different people so far. For 2 it fails, but for 1 it runs fine and I'm out of ideas for why that might be the case. Sketch: /* * This sketch...

Here's the DigitalIO library from Bill which has software SPI implementation (SoftSPI.h): https://code.google.com/p/rtoslibs/downloads/detail?name=DigitalIO20130221.zip&can=2&q=. It relies on DDRx, PINx and PORTx, thus compiles only on AVRs. I tried to create a pinMap[] for ARM based on this...

At the moment I'm trying to use software SPI to make my ADC+Teensy+SD setup to work, I was wondering if there are any developments improving the speed of the software SPI on Teensy 3.0 or its implementation on ARM at all? It seems like all of the available libraries are made for AVR and don't...

Cool, thanks!

I'm using the sdfatlib from here: https://code.google.com/p/sdfatlib/downloads/list. Based on what I've read it provides the fastest access to the card. Based on this post (http://forum.pjrc.com/threads/25582-SPI-sharing-between-interrupts-and-main-program?p=45745&viewfull=1#post45745) Paul is...

I'm try to interface the three components in the title to make a data-logger capable of sampling physiological signals directly. To minimise the number of connections, the ADC and the SD card are to share the SPI bus. The problem I've encountered is that if I initialise and setup the files on...