DW1000 User Manual
© Decawave Ltd 2017
Version 2.12
Page 102 of 242
register file 0x17 reports the transmit time stamp information. During frame transmission the
start of the PHR is the nominal point which is time-stamped by the IC. The IEEE 802.15.4 UWB standard calls
this point the RMARKER. The DW1000 takes a timestamp of the symbol in which the RMARKER event occurs
and to this adds the antenna delay to give a resultant time stamp value, of when the RMARKER is launched
from the antenna.
This TX_TIME register contains the following sub-fields:
REG:17:00 – TX_TIME – Transmit Time Stamp (Octets 0 to 3, 32-bits)
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
(low 32 bits of 40-bit value)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
REG:17:04 – TX_TIME – Transmit Time Stamp (Octets 4 to 7, 32-bits)
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
(low 24 bits of 40-bit value)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
REG:17:08 – TX_TIME – Transmit Time Stamp (Octets 8 to 9, 16-bits)
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
(high 16 bits of 40-bit value)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Register file: 0x17 – Transmit Time Stamp
are laid out above in a map that is 32 bits wide. It
is possible to read a variable number of bytes any byte index. The individual sub-fields are described below:
Field
Description of fields within Register file: 0x17 – Transmit Time Stamp
TX_STAMP
reg:17:00
bits:39–0
This 40-bit (5-octet) field reports the fully adjusted time of transmission. The unit of the least
significant bit is approximately 15.65 picoseconds. The actual unit may be calculated as 1/
(128*499.2×10
6
) seconds. The value is available here when the PHR transmission has
completed.
TX_RAWST
reg:17:05
bits:39–0
This 40-bit (5-octet) field reports the Raw Timestamp for the frame. This is the value of the
system clock (125 MHz) captured at the time of the first chip of the first PHR symbol. The
precision here is approximately 125 MHz, i.e. the 9 least significant bits are zero.
7.2.26 Register file: 0x18
– Transmitter Antenna Delay
ID
Length
(octets)
Type
Mnemonic
Description
0x18
2
RW
TX_ANTD
16-bit Delay from Transmit to Antenna
register file 0x18, the Transmitter Antenna Delay, is used to account for the delay between the
internal digital timestamp of the RMARKER (at the start of the PHR) and the time the RMARKER is at the
antenna. The value programmed here is automatically added to the raw timestamp TX_RAWST to get the
TX_STAMP reported in