DW1000 User Manual
© Decawave Ltd 2017
Version 2.12
Page 203 of 242
Enable CW mode:
PGTEST to 0x13 to enable Continuous Wave (CW) Test Mode.
Set trim register to mid-range setting, e.g. 0x0F, whilst maintaining the required reserved values in the most
significant bits of the register, see reserved field notes for
Sub-Register 0x2B:0E – FS_XTALT
Sub-Register 0x2B:0E – FS_XTALT
While monitoring the CW frequency, adjust the trim register (5 bits) until the desired frequency is obtained.
Figure 30 shows that the trimming is typically linear and usually the final value is reached with just one or
two adjustments.
The crystal trim value should then be stored on the OTP memory, see section
for details of how to program OTP memory and recommended memory locations.
In DW1000 applications using crystal trimming, the calibrated crystal trim value should be read by the
application from OTP memory as part of setup and programmed into the
Sub-Register 0x2B:0E – FS_XTALT
This register is preserved in the AON memory as long as the IC is powered. This facilitates the use of the trim
value when the IC wakes up from
or
Figure 29: PPM vs Crystal Trim Setting, V
BATT
= 3.3 V
8.2 IC Calibration
– Transmit power and spectrum
In order to maximise range, DW1000 transmit power spectral density (PSD) should be set to the maximum
allowable for the geographic region of deployment. For most regions this is -41.3 dBm / MHz. DW1000 is
-60.00
-40.00
-20.00
0.00
20.00
40.00
60.00
0
5
10
15
20
25
30
PPM
Trim Code
3.3V