Hello,
I have an issue with my Artemis Openlog (SKU number : DEV-16832),
When I use it by the USB port to a computer, it’s works well, it logs normally,
But when I use it with an external 3V3 power supply, the LED blink only one time and the Artemis doesn’t start, sometimes, I can start it with the Reset button, but I need to push the reset button a few times to start it,
I also try to put 5V on Vin, but, same problem,
For your information, I measured some potentials:
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RST: 4mV
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3.3 V: 3.3V
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VCC_ 1: 3V
I tested without the micro SD card, and the LED blinks once.
And I also tried with C2=10uF, but same…
Thank you for your help,
Alexandre
Are you using soldered connections? Maybe share a photo of the working vs non-working setups
The RST level is same between the working and non working setup → 4mV
Do you have a qwiic-enabled mcu you can try with it?
That appears wired correctly…did you happen to use external power + usb at the same time?
Normally it’s not enable, because I didn’t use it.
I tried with only an external power supply, only usb and both together, it’s the same problem.
OLA_settings.txt (1.5 KB)
Both together can damage the board… " On the back of the board, you will notice that there is a pin labeled VIN. We don’t recommend it, but you can also feed in external power (recommended operating voltage of 6.0V Maximum ) via the VIN pin next to breakout pin 11. We don’t recommend it because there is no protection diode between this pin and USB-C 5V power. If you have VIN and USB-C connected at the same time, bad things could happen. If VIN is your only option then we recommend cutting the MEAS jumper to isolate VIN from USB 5V and the LiPo." from OpenLog Artemis Hookup Guide - SparkFun Learn
I only use both together when I configured the OpenLog.
Now, the problem is the RST voltage level… it stay at 4mV, normally it’s 3.3V?
I have taken my Openlog and measured on the RST testpoint that is next to the uSD card in your picture. This testpoint is directly connected to the reset-switch. I measure 3V on reset signal either connected to USB OR connected to external battery.
Doing an ohm measurement between GND and the RST testpoint when NO power is connected I get ~2M, which I would expect to be high.
Measuring Ohm between the VCC_1 and RST testpoint when NO power is connected, I get ~99.7K, which I expected from R28.
The 4mV you measure looks incorrect to me. That it works on USB connection might the from Artemis_RTS signal that triggers BOTH BOOT and RESET.
Between GND and the RST testpoint without any power supply, I measure 630kohms
Between Vcc_1 and the RST testpoint without any power supply, I measure 750kohms
I agree with you about the RST level, it’s not normal…
750K is incorrect high. Given the single R28 100K pull-up resistor between VCC-1 and reset. I also think the 630K is too low.
I expect this board has a HW problem (either component or broken circuit). I would return it where you have bought it and ask for replacement.
Was it purchased from us? If so head over to Return Policy - SparkFun Electronics (contact vendor if purchased elsewhere) and we’ll get ya squared away
