DW1000 User Manual
© Decawave Ltd 2017
Version 2.12
Page 105 of 242
power saving is dependent on the configured on/off times for this sampling. See additionally section
2.4.2 –
Specific state sequences supported by the DW1000
and
discussion. The configuration consists of the fields identified and described below:
REG:1D:00 – RX_SNIFF –SNIFFMode Configuration
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
- - - - - - - - - - - - - - - -
SNIFF_OFFT
- - - - SNIFF_ONT
- - - - - - - - - - - - - - - -
0
0 0 0 0
0
The individual sub-fields are described below:
Field
Description of fields within Register file: 0x1D – SNIFF Mode
-
Bits marked ‘-’ are reserved.
SNIFF_ONT
reg:1D:00
bits:3–0
SNIFF Mode ON time. This parameter is specified in units of PAC. For details of PAC and its
role inPreamble Detection, please refer to section
. A value of zero
will disable SNIFF Mode. A non-zero value will enable Preamble Detection Mode and select
how long the receiver is turned on during the preamble hunt. NB: This must be a minimum of
2 for the IC to correctly make a preamble detection decision. If preamble is detected during
this time window the receiver will remain on and will continue to attempt reception of the
frame. If no preamble is detected the receiver will be returned to idle mode for the time
configured by the SNIFF_OFFT parameter before sampling the air again.
SNIFF_OFFT
reg:1D:00
bits:15–8
SNIFF Mode OFF time specified in µs. This parameter is specified in units of approximately 1
µs, or 128 system clock cycles. A value of zero will disable SNIFF Mode. A non-zero value will
enable SNIFF Mode and select how long the receiver is turned off for during the preamble
hunt. Please refer to the SNIFF_ONT description above for more details of this feature.
As an example, with a 1024 preamble length, a roughly 50% duty cycle (on 50% and off 50%) can be
configured with a PAC of 8 symbols, SNIFF_ONT set to 3 PAC intervals, and SNIFF_OFFT set to 24
microseconds. The performance cost of this in terms of range is < 1 dB.
7.2.31 Register file: 0x1E
– Transmit Power Control
ID
Length
(octets)
Type
Mnemonic
Description
0x1E
4
RW
TX_POWER
TX Power Control
register file 0x1E is used for configuration and control of the transmitter output power.
Normally it is desired to transmit at (just under) the maximum power allowed by the regulations for the
geographic area of deployment simply because the higher the power the further the signal will go, although
in some circumstances it may be desired to reduce the power to limit the operating range or for other
reasons.
To optimise performance it is necessary (because of variations in the RF circuitry both internal to the IC and
in the external components) to verify the output power during module manufacture testing and store a
calibration value to set the module’s output power as high as possible within the limits of the regulations.
(The DW1000 has an area of OTP memory reserved for this. Please refer to section 8