These informations are extrapolated from the DW1000 user manual.

About the DW1000. Chapter 1.

The DW1000 is a fully integrated low power, single chip CMOS radio transceiver IC compliant with the IEEE 802.15.4-2011 ultra-wideband (UWB) standard.

• It facilitates proximity detection to an accuracy of +/- 10 cm using two-way ranging time-of-flight (TOF) measurements.
• It facilitates real time location of assets in to an accuracy of +/- 10 cm using either two-way ranging (TOF) measurements or one-way time difference of arrival (TDOA) Time Difference of Arrival schemes
• It spans 6 RF bands from 3.5 GHz to 6.5 GHz
• It supports data rates of 110 kbps, 850 kbps and 6.8 Mbps
• Its high data rates allow it to keep on-air time short and thereby save power and extend battery lifetimes
• Its ability to deal with severe multipath environments makes it ideal for highly reflective RF environments

Clock Periods and Frequencies

The chipping rate given by the IEEE 802.15.4-2011 standard [1] is 499.2 MHz. DW1000 system clocks are referenced to this frequency. Where the system clock frequency is given as 125 MHz, this is an approximation to the actual system clock frequency of 124.8 MHz. Similarly, where the system clock period is given as 8 ns, this is an approximation to the actual period of 1/ (124.8×106) seconds. The 1 GHz PLL clock, where referenced, is an approximation to its actual frequency of 998.4 MHz. A 63.8976 GHz sampling clock is associated with ranging for the IEEE 802.15.4-2011 standard, where a 15.65 picosecond time period is referred to, it is an approximation to the period of this clock.

PRF

PRF values of 16 MHz and 64 MHz are given in this document. These are approximations to the PRF values dictated by [1]. PRF mean values are slightly higher for SHR as opposed to the other portions of a frame. Mean PRF values are 16.1/15.6 MHz and 62.89/62.4 MHz. Refer to [1] for full details of peak and mean PRFs.

Data Rate

Where a data rate of 6.8 Mbps is referred to, this is equivalent to the 6.81/6.8 Mbps data rate in

Interfacing to the DW1000. Chapter 2.

The SPI Interface

The DW1000 host communications interface is a slave-only Serial Peripheral Interface (SPI) compliant with the industry protocol. The host system must include a master SPI bus controller in order to communicate with the DW1000.The SPI bus signals, their voltage levels and signal timings are described in the DW1000 data sheet. The host system reads and writes DW1000 registers via the SPI.

SPI operating modes

The operating mode of the SPI is determined when the DW1000’s digital control function is initialised as a result of a device reset or as it is woken up from a sleep state. At this time GPIO lines 5 and 6 are sampled and their values act to select the SPI mode.

Transaction formats of the SPI interface

Interrupts

The DW1000 can be configured to assert its IRQ pin on the occurrence of one or more status events. The assertion of the IRQ pin can be used to interrupt the host controller and redirect program flow to deal with the cause of the event.

DW1000 Operational States. Chapter 2.3.

##State diagram The DW1000 has a number of different operational states (or modes). These are listed and described in Table 1(DW1000 user manual) and the transitions between them are illustrated in Figure 8 (DW1000 user manual).

Default Configuration on Power Up. Chapter 2.5, DW1000 User Manual.

DW1000 is a highly configurable transceiver with many features. The register reset values have been selected with the intention of minimising user configuration required. The default configuration may be summarised as being channel 5, preamble code 4 and mode 2. Channel numbers and preamble codes are as specified in the standard, IEEE 802.15.4-2011 [1] and mode 2 is as specified in the DW1000 data sheet modes .

Message transmission. Chapter 3.

The transmission of data frames is one of the basic functions of the DW1000 transceiver.

Message Reception. Chapter 4.

The reception of a frame is enabled by a host request or by an automatic re-enabling of the receiver. The receiver will search for preamble continually until preamble has been detected or acquired, when a demodulation will be attempted. A preamble detection timeout may be set to allow the receiver to stop searching for preamble after a desired period.