DW1000 User Manual
© Decawave Ltd 2017
Version 2.12
Page 39 of 242
Clear RX event flags in
SYS_STATUS reg:0F; bits FCE,
FCG, DFR, LDE_DONE
Set TXRXOFF bit = 1, in reg:0D,
to disable the receiver
Mask Double buffered status
bits; FCE, FCG, DFR, LDE_DONE
to prevent glitch when cleared
Unmask Double buffered status
bits; FCE, FCG, DFR, LDE_DONE
Figure 15 : TRXOFF in Double-Buffered Mode
4.3.5 Overrun
An overrun condition may occur in the IC receiver if the host side is not keeping up with the arrival rate of
frames. So for example, say the IC receives a frame into the first buffer, moves on to the other buffer and
places a receive frame in it also. The IC will then move back to point to the first buffer again. If the host has
not completed reading the data from this first buffer (i.e. not yet issued the HRBPT) then the IC will not
overwrite that buffer with any new frame if one arrives. If a new frame arrives and the IC is unable to write
data to the buffer (because the host has not issued the HRBPT), then this is gives rise to an overrun
condition. The overrun condition occurs at the point the receiver finishes processing a good PHY header and
needs to write the first octet of data to the RX buffer. This event is detected by the IC and reported in the
RXOVRR status bit in
Register file: 0x0F – System Event Status Register
When a receiver overrun occurs, the frame reception in progress will be aborted and, assuming RX auto-re-
enable is enabled (by RXAUTR) the receiver will begin looking for preamble again. The overrun condition and
the RXOVRR status bit will be cleared as soon as the host issues the HRBPT command. Receiver overrun
events are also counted in
Sub-Register 0x2F:0E – RX Overrun Error Counter
, assuming that counting is
enabled by the EVC_EN bit in
Sub-Register 0x2F:00 – Event Counter Control
The overrun condition results in the corruption of the good frames previously received. The RX_FINFO,
RX_TIME and RX_FQUAL registers are affected. Received frames must be discarded due to corruption if an
overrun (RXOVRR) occurs. A receiver-only reset must be applied to the receiving device to clear the
errored state which may persist, see Figure 14. See the SOFTRESET field of
for details of how to apply the receiver-only reset.
The impact of overrun corruption of previously received frames needs to be evaluated carefully in the
intended application. For instance, if overruns can occur the system should not use automatic
acknowledgements (see AUTOACK in SYS_CFG
, as a corrupt frame will be acknowledged but then
discarded.
4.4 Low-Power Listening
Low-power listening is a feature whereby the DW1000 is predominantly in the
periodically for a very short time to sample the air for a preamble sequence. If no preamble is seen the
DW1000 automatically returns to
for another period, however if preamble is seen the DW1000 does
