DW1000 User Manual
© Decawave Ltd 2017
Version 2.12
Page 104 of 242
Field
Description of fields within Register file: 0x1A – Acknowledgement time and response time
ACK_TIM
reg:1A:00
bits:31–24
Auto-Acknowledgement turn-around Time. This 8-bit field is used to configure the turn-around
time between the correct receipt of a data frame (or a MAC command frame) and the
transmission by the DW1000 of the acknowledgement frame. The time here is specified in
units of preamble symbols. (This resultant time is slightly different depending on whether the
PRF is 16 or 64 MHz, see Table 60 for details the preamble symbol lengths).This timer only
applies if auto-acknowledgement is in use and then only acts when the frame is correctly
received, passing through the RX frame filtering rules, and when the ACK bit in the frame’s
MAC header is set to request acknowledgement. Please refer to section
for details of the Automatic Acknowledgementfunction. To ensure that the
receiver is ready for the first preamble symbol, and assuming that the remote DW1000 has a
its W4R_TIM parameter set to 0, the recommended minimum ACK_TIM settings are as follows:
Data Rate
Recommend min.
110 kbps
0
850 kbps
2
6.8 Mbps
3
This is most important at the 6.8 Mbps data rate, where preamble sequences are generally
short, and losing even a few preamble symbols could potentially compromise ACK reception.
Where the W4R_TIM parameter is larger than zero, the ACK_TIM setting should be increased
also to ensure that none of the frame is sent before the remote receiver is listening.
-
Bits marked ‘-’ are reserved and should always be written as zero.
7.2.29 Register files: 0x1B and 0x1C
– Reserved
ID
Length
(octets)
Type
Mnemonic
Description
0x1B
-
-
-
Reserved – this register file is reserved
0x1C
-
-
-
Reserved – this register file is reserved
register file 0x1B and 0x1Care reserved for future use. Please take care not to write to these
registers as doing so may cause the DW1000 to malfunction.
7.2.30 Register file: 0x1D
– SNIFF Mode
ID
Length
(octets)
Type
Mnemonic
Description
0x1D
4
RW
RX_SNIFF
Sniff Mode Configuration
register file 0x1D is used for configuration of SNIFF mode, which is a power saving technique
that can be employed to reduce the power consumption of preamble detection. For normal preamble
reception the receiver searches for preamble continually, while in SNIFF mode the receiver samples (“sniffs”)
the air periodically on a timed basis returning to receiver idle mode in between.
The transmitting device needs to be sending a sufficiently long preamble to allow for the SNIFF mode to
operate and leave sufficient preamble remaining thereafter to get a good reception and RX timestamp. The