SparkFun Forums

[StockBrick]

A novice question.

I've uploaded the LSM9DS1_Basic_SPI example to the RedBoard Artemis ATP with no errors.

When the LSM9DS1 is disconnected from the ATP the power LED on the ATP is on and I correctly get the following message via serial:
Opening port
Port open
Failed to communicate with LSM9DS1.
Double-check wiring.
Default settings in this sketch will work for an out of the box LSM9DS1 Breakout, but may need to be modified if the board jumpers are.

When I connect the LSM9DS1 the power LED on the ATP stays off and the serial port fails to open with the following message:
Opening port
Debug off
Port failed to open

I plugged in an external power supply to see whether that made any difference but it didn't.

Any ideas what is wrong?

Thanks

[paulvha]

looks to me your power is short circuit somehow as the power-led on the ATP stays off. The first messages are coming from the sketch, not sure where the second messages (with the LSM connected) are coming from, but it does not look to me from the sketch. Check that your power supply connection. E.g. first only connect the VDD and GND and see that the power led stays on etc.

[StockBrick]

Thanks Paul. The LED is off when just VDD and GND are connected. There are no obvious soldering problems with the headers although I am new to that. Is there a way of testing for problems with the sensor breakout eg with a multi-meter or oscilloscope?

The second message about it not being possible to open the port is output from the VisualMicro serial monitor.

[paulvha]

not good... means it has a short circuit somewhere. This is very basic that you can try to detect with a multimeter. I expect a (close to) zero resistance if you measure on the LSM between VDD and GND. double check on soldering.. but else (by looking at the schematics) there is only the LSM that could cause it a close to zero resistance.

[StockBrick]

GND TO VDD- approx 2 Ohms
GND TO SDA - continuity approx 36 Ohms

Is that normal?

Should I be measuring the resistance across any of the other pins?

[paulvha]

VDD to GND with 2 ohms is like a short circuit. Not Good.. GND to SDA does not tell a lot. I am afraid your board is defective unless you find soldering that could cause this. Maybe it got powered with 5V and then it will be over.

[StockBrick]

I've been quite careful but possibly. What should the resistance be between GND and VDD?

[paulvha]

According to the datasheet in normal working mode (and you have not reached that point) the max current is 4 + 0.6 = 4.6 mA at an operating voltage of 2.2V. So the resistance would be around 2.2V / 4.6mA = 550 ohm. It does not specify the current in standby but it is save to say it should be (much) more than 550 ohm.

[StockBrick]

Thanks. Looks like I need to buy another one when they come back into stock. In the meantime I'll try another sensor. I didn't use much of it but could 'no clean' flux cause the problem?