SPI Length

[canye23]

Hello, 

I have successfully managed to connect accelerometer adxl345 to Labview with Arduino with SPI(4-wire connection+3.3V+GND) and get the right values.I use wires with length 15cm each. I want to increase this length, but every time I add new wires the accererometer seems to stop working. To be more specific it is powered on but it gives no values. I have read that distance affects the SPI but can this be the problem when increasing the distance by only 15cm ? 

[bseguin]

Increase distance = decrease speed of communication and add filtering to keep the signal as high as possible and as low as possible for the 1s and 0s

Benoit

[canye23]

Dear besguin, 

Thank you for your reply.

Wouldn’t the problem be the same if I connected the accelerometer via i2c? 

[bseguin]

Yes and no...

do not twist your I2C wires and longer it is slower it is.

I suggest you to use oscilloscope to evaluate your wire.

Here I have over a meter of wire with I2C without issues at a 100K speed.

Benoit