Hello,
I currently try to measure the xtal frequency of my DW3000 chips. Application Note APS312 mentions many options of how to measure the frequency. I wanted to use the GPIO output mentioned in section 3.3.1.6 as it is the most approachable for me right now.
In this section it states that 0x3 should be written to register 0x05:00. The DW3000 manual itself states that I should in fact not write 0x3 to the register:
011 – 111: Reserved. Do not select this value.
Ignoring this statement (btw quite odd to have those contradictory statements in official documents) I’ve written 0x3 to the register.
Measuring the frequency with an oscilloscope (don’t have a frequency analyzer at hand right now but just wanted to check if it works in general) I just get a steady output of 150mV - no sin wave or any AC in general tho.
My question is:
Should really 0x3 be written to this register? Has there anything else to be modified in the register (e.g. changing 0x5:08 to 0xFE to assign it as an output)? Or does anyone have experience with this method of calibration and can comment on it?
Kind regards
Fhilb