DW1000 User Manual
© Decawave Ltd 2017
Version 2.12
Page 53 of 242
Please refer to the standard [1] for details of this. The DW1000 does not automatically determine the frame
pending bit inserted into the automatically-generated ACK frames. Instead it copies the value of the
AACKPEND configuration bit (from
Register file: 0x04 – System Configuration
), which is zero by default.
5.3.5 Host Notification
Register file: 0x0F – System Event Status Register
) indicates that an acknowledgement
has been requested. The AAT bit is set at the same time as the RXFCG event status (indicating a good CRC at
the end of frame reception).
If automatic acknowledgement is enabled then the AAT bit can be used during receive interrupt processing
to detect that acknowledgement is in progress and so avoid taking any action until the transmission of the
acknowledgement is completed, and signalled by the TXFRS (Transmit Frame Sent) event.
Note: If automatic acknowledgement is not enabled, then the AAT status bit must be ignored.
Note: there is a situation that can result in the AAT bit being set for the current frame as a result of a
previous frame that was received and rejected due to frame filtering. This is despite the fact that the current
frame is not requesting an automatic acknowledgement. In this circumstance an automatic
acknowledgment is
not
actually transmitted, however the fact that the AAT is set could cause the user to
wait for a non-existent automatic acknowledgement process to complete.
In this situation, when automatic acknowledgement is enabled and the AAT bit is observed as set, to avoid
waiting for the acknowledgement process to complete and TXFRS to be set, the Acknowledgment request
field in the frame control section of the MAC header of the received frame as described in Section 11.2.4
should be checked to confirm that the current frame has actually requested an automatic
acknowledgement. If the Acknowledgment request field is cleared, then the user should clear the AAT bit in
the status register
Register file: 0x0F – System Event Status Register
(as well as in any copy of the status
register that is returned to the user callback when using interrupts).
5.3.6 ACK Frame Corruption
The data in the Auto ACK frame can be corrupted if a read access is made to either TX_FCTRL or TX_BUFFER
during Auto ACK frame transmission.
5.4 Transmit and automatically wait for response
The DW1000 has the ability to automatically turn on its receiver after a transmission has completed in order
to receive a response. This may also include an optional delay configuration between the end of the
transmission and the enabling of the receiver. This is controlled by the WAIT4RESP bit in
and the W4R_TIM parameter in the
Register file: 0x1A – Acknowledgement time and
Note:
If the response that is received is a frame requesting an acknowledgement frame, the DW1000 will
transmit the ACK if automatic acknowledge is enabled, but the receiver will re-enable following the
transmission of the ACK. Depending on host response times this may allow the acknowledge-requesting
