Davidelvig
Senior Member

Thanks. I'm hesitating a bit at the price. I'm going to search for, and or start a new thread specifically on RTC and battery life. I have taken this thread too far from its title.

Sorry, this RTC on JLCPCB, the NXP PCF8563T with data sheet here As it happens, a "Basic" part on JLCPCB

Thanks, @BriComp! That looks like it is fully stand-alone - i.e. with an embedded crystal. Is that your read? It would work with a just few R's and C's? I've been perusing JLCPCB/parts and found this, though I...

One more clarification/question before I consider enclosure redesign and battery selection: - is it possible to get lower VBAT drain in any way and still get RTC? - can I de-power the T41 board without using the...

OK, with this and another thread, my conclusions are: - the OnOff pin on the Teensy 4.1 is really cool! It allows me to eliminate a similar circuit from my daughterboard to provide push-button on-off. - the function...

That's helpful. Thanks! I think I need to account for battery replacement in the field

That’s more reassuring. My product has been in the field with Teensy 3.2 for about a year. No known dead batteries. With 1.5-2 year coin cell life, I’ll want to consider customer change-ability, or an easy mail-in...

I’m reluctant to revive an old post, but… Is this still a thing? My new design moves from Teensy 3.2 to 4.1. I’ve been relying on VBAT to keep the RTC alive “forever” Do I need a different solution for that? Short...

I’ve had help on the original issue leading to this post and the main problem is solved. The post on VBAT was an extra bonus!

Thanks, and wow! I had not considered easy swapping on the coin cell in my design. I’ll have to mull this over.

UN-DEAD! Thanks so much to Netherlands PaulS Had a misplaced voltage regulator (AP7313) on my board, using the Teensy's 3v3 output as the IN input. Knocking that part off the circuit disabled my SGTL5000, but the...

Yes. I'll give that a go.

Upon connecting USB, and as the chip rapidly heats up, the 3v3 pin on the Teensy 4.1 rises to 0.95v This while soldered on to my daughterboard (51 pins soldered). The Daughter board has no LiPo bat connected...

With further review, I don't think LiPo was reversed. My clear questions at present are: What sorts of inputs would cause the TPD3S014 to overheat quickly Would that overheating lead to a bricked Teensy? ...

Thanks, @MarkT You mean like this, and then, during testing, apply side pressure... with no solder until testing passes?

A quick bump to see if anyone has experience of advice regarding using offset/locking PCB hole patterns for mounting a Teensy.

Got it. So some power from the coin cell (in my case) on VBAT keeps something in the MCU charged so that grounding On/Off can cause a startup (but only if there’s power at startup time on VIN to actually power a start...

I think I tested the power with LiPo unplugged, and just USB. I’ll try again on LiPo only with an ammeter in line.

Oh my goodness! It solves it all for me! - I disconnected pin 16 from On/Off and the push-button on-off works as expected with 5-second off and 1/2 second on. - then I run your three lines of code at a time of my...

OK, I've found the simple reproducible case (using Blinky example code). The Teensy 4.1 On/Off pin works as expected if On/Off is not otherwise connected to any pin. If I connect a GPIO pin to that On/Off pin,...

Advice from ST Micro seems to be: - enter I2C commands sufficient to disable I2C. Then use SPI. So, since I have a pull-up resistor on CS, and this can be the I2C active mode (on start-up), and since the shared...

I submitted a support request to ST Micro documenting the saga, and asking for best practices when using this chip for SPI comms. I'll report back. Thanks, all, for your help!

I'm sure the FAIL is in my circuit, and not likely a problem with the Teensy 4.1 I expect some fails... that's why I did the minimum order ;) If I can get this to work (and I expect I will) it eliminates a chunk of...

Thanks for your help. I need to create a simpler test system for using the On/Off button. My current board is a "fail" in that circuit at the moment.

I just edited the post. Does that .14v drop seem right?

I clearly have the wrong CR2032 battery holder on this board. I'll need to rig an alternate connection for a coin cell for testing. Stay tuned! ... minutes later... OK, I rigged up the battery holder to deliver...

I have a coin cell installed, and VBAT reads 3.17v when the system is On. After successful shutdown (via On/Off pin grounding): - On/Off pin reads 0.4v - VBAT pin floats below 0.2v down to about 50mV I've not...

Thanks @sicco. While the original Teensy SPI-transaction-based coded just worked on my custom board, I'll be trying to break it. And bolster it. It is a strange catch-22. And I think I'll submit a ticket to ST...

The board is designed by me and produced at JLCPCB. and the IMU MEMS chip has this local schematic around the IMU

Here's something interesting - and delightful for me! My new board has arrived, with the schematic as in post #20 above. It works! The code in the app is this at IMU start-up... very similar the test code I used on...

I had not changed the wires... I now have: - MISO (12) to SDA - SCK (13) to SCK - CS (10) to CS - MOSI (11) not connected Now with your first set of code (version a) I get this output:

I modified the code to fit as I thought would fit (commenting the magnetometer code). Here's the output:

Paul, I just read your article here. Would you suggest I try tri-stating the MISO line and see how it behaves? The only other SPI device in the loop is the on-board SD card on the Teensy 4.1. ...minutes later......

Thanks, Paul!

Arrrgh! It might be better to choose another chip, I think. I'm still hoping that I've done something dopey, and that changing that would make it all work. But the setup seems the same on 3.2 and 4.1 I'm happy...

I've done these changes and still see success with T3.2 and failure with T4.1. While I think the commands cause the reboot, I don't have a direct way to check that. OK, updated code here: #include <SPI.h> #define...

Thanks. My intent was 4-wire, but who knows what random start-up bits can trigger... and what VDD caps can persist between runs. I'm thinking my path is now: - make a write call to set the BOOT flag (bit 0) in...

Thanks Paul. I did indeed photograph one setup with the Teensy 4.1 pins incorrect. Testing was with the correct pins (10-13). I been doing the same tests using an off-the-shelf teensy 3.2 board, and it works. The...

I could not find a Sparkfun or Adafruit board with STM IMU chips. I could order one of these and send it to you. Hang on... I find this now at AdaFruit. It's an ST LSM6DS3TR-C, but it may be analogous. I'll check...

It is indeed an ST MEMS chip. I've tried a couple of other variations based on trying to keep the I2C subsystem off, as you suggest. I removed the 10K pull-up resistor on the CS pin I even tried pulling it down...

Thanks! Now I can see the note in the I2C section of the data sheet on STOP for I2C I've adapted the code here. Unfortunately, no change in results. Still works as before on Teensy 3.2, but fails to return the...

Solved. I had the midi.c file in a subdirectory within my Platform project in VS Code. Placing the file in the /src directory solved the problem. It seems that files in the /src are always included. Files elsewhere,...