Hi,
I think I've got a situation where the external power into my Teensy 3.2 is marginal at startup. Let me explain the context and I'd be glad to hear any suggestions for things I can do in code to make it more tolerant, or if the issue may arise from something else?
I made a little Eurorack module (see this thread https://forum.pjrc.com/threads/6782...e-to-show-and-a-question-about-Teensy-3-2-DAC) and it is sometimes not starting up in the rack.
Here's what I see:
Now the device uses an Adafruit LED Array with i2c backpack (bought from Mouser, not Aliexpress), and I expect the initialisation of this is the problem (combined with other modules startup power demands).
I have tried adjusting the TEENSY_INIT_USB_DELAY_BEFORE/TEENSY_INIT_USB_DELAY_AFTER delays to make the device effectively startup a bit later, but to no avail. Is there a better way to do this?
The USB is only used when programming or testing on a laptop, so I do compile with USB+MIDI+Audio. Should I just set USB Type to No USB to minimise startup power demands?
Now I will try and rearrange the power connections on my rack since there are 3 separate zones, but that requires a lot of unscrewing of modules so I won't do it until after I've considered alternatives. At the moment there is enough space for me to reach in and reconnect when I need to.
Maybe I should just add a manual on/off switch to the panel? But that's less than ideal.
Thanks in advance for any suggestions.
I think I've got a situation where the external power into my Teensy 3.2 is marginal at startup. Let me explain the context and I'd be glad to hear any suggestions for things I can do in code to make it more tolerant, or if the issue may arise from something else?
I made a little Eurorack module (see this thread https://forum.pjrc.com/threads/6782...e-to-show-and-a-question-about-Teensy-3-2-DAC) and it is sometimes not starting up in the rack.
Here's what I see:
- Startup is 100% reliable when powered by USB.
- Startup is 50% (more or less) when powered by a Eurorack cable (12V to 78L05 regulator to Vin with the usual capacitors)
- I measure 5V and 3.3V on the appropriate pins even when it is not working.
- The intermittent startup behaviour occurs even with the Blink sketch.
- Startup is 100% reliable when unplugging and replugging the connector after the rack has been turned on.
- Startup is 100% reliable on another (much less populated) rack.
- The modules (as specified) are not close to the current limits the rack should be able to provide (It is a TipTop Mantis with a 3A power brick).
- The same behaviour happens if overclocking to 120MHz or running at 72MHz.
Now the device uses an Adafruit LED Array with i2c backpack (bought from Mouser, not Aliexpress), and I expect the initialisation of this is the problem (combined with other modules startup power demands).
I have tried adjusting the TEENSY_INIT_USB_DELAY_BEFORE/TEENSY_INIT_USB_DELAY_AFTER delays to make the device effectively startup a bit later, but to no avail. Is there a better way to do this?
The USB is only used when programming or testing on a laptop, so I do compile with USB+MIDI+Audio. Should I just set USB Type to No USB to minimise startup power demands?
Now I will try and rearrange the power connections on my rack since there are 3 separate zones, but that requires a lot of unscrewing of modules so I won't do it until after I've considered alternatives. At the moment there is enough space for me to reach in and reconnect when I need to.
Maybe I should just add a manual on/off switch to the panel? But that's less than ideal.
Thanks in advance for any suggestions.