DW1000 User Manual
© Decawave Ltd 2017
Version 2.12
Page 75 of 242
The fields of the TX_FCTRL register identified above are individually described below:
Field
Description of fields within Register file: 0x08 – Transmit Frame Control
TFLEN
reg:08:00
bits:6–0
Transmit Frame Length. Standard IEEE 802.15.4 UWB frames can be up to 127 bytes long. The
value specified here determines the length of the data portion of the transmitted frame. This
length includes the two-octet CRC appended automatically at the end of the frame, unless
SFCST (in
Register file: 0x0D – System Control Register
) is use to suppress the FCS. The frame
length is also copied into the PHY Header of the TX frame so that the receiving device knows
how much data to decode.
TFLE
reg:08:00
bits:9–7
Transmit Frame Length Extension. The DW1000 supports a non-standard mode of operation
with data frame lengths up to 1023 bytes. This mode of operation is enabled via the
PHR_MODE selection bits of
Register file: 0x04 – System Configuration
. In this long frame mode
TFLE adds three high-order bits to TFLEN to extend the frame length to 10-bits, allowing frame
length from 0 up to 1023 bytes to be sent. Please refer to section
for more details of this non-standard mode.
R
Reserved. Bits 12, 11 & 10 are reserved for future expansion. They should be set to zero.
TXBR
reg:08:00
bits:14,13
Transmit Bit Rate. This sets the user bit rate for the data portion of the frame as follows:
Bit 14
Bit 13
Bit Rate
0
0
110 kbps
0
1
850 kbps
1
0
6.8 Mbps
1
1
reserved
TR
reg:08:00
bit: 15
Transmit Ranging enable. This bit has no operational effect on the DW1000; however it is
copied into the ranging bit in the PHY header (PHR) of the transmitted frame, identifying the
frame as a ranging frame. In some receiver implementations this may be used to enable
hardware or software associated with time-stamping the frame. In the DW1000 receiver the
time-stamping of the receive frame does not depend or use the ranging bit in the received
PHR.
TXPRF
reg:08:00
bits:17,16
Transmit Pulse Repetition Frequency. This sets the mean Pulse Repetition Frequency (PRF)
used in the transmitter:
Bit 17
Bit 16
Nominal PRF
0
0
4 MHz
0
1
16 MHz
1
0
64 MHz
1
1
reserved
Note: (a) For successful reception of a frame the PRF in the receiver needs to be
configured to be the same as the PRF used for transmitting the frame.
(b) The choice of preamble code also needs to be appropriate to the configured PRF
and needs to be the same in both transmitting and receiving ends for successful
communication – please use Table 61 to select the appropriate preamble code.
(c) The DW1000 receiver does not support the 4 MHz PRF.