Those are the values (or close to them) in the standard decawave libraries, if you are using their drivers and haven’t changed the values then that’s roughly what you will currently be using.
They are the delay as measured in the decawave internal clock cycles at 128 * 499.2 MHz or roughly 15.65ps. At the speed of light 15.65 ps works out as roughly 5 mm.
A ~6m jump in antenna delay is not normal. If you have a high transmit power and very short range then you can get some odd effects caused by the signal getting picked up by PCB traces or even the internals of the chip and so experiencing a shorter delay than normal. If you decrease the transmit power then this will probably go away.
Sorry, my mistake. It is 0.7m delay.
So the difference between short range and long range is of from 0.5m delay to 0.7m delay.
I have tried changing the TX_ANT_DLY and RX_ANT_DLY value. But i am still getting the same delay difference between two ranges.
Is there any specific reason for this?
The Rx and Tx delays are constant values, all they are going to do is add or remove a constant from the range so there is no way they could correct for this.
The error being 20 cm shorter at short range than at long range is in the region of what you would expect due to signal strength changes. As previously mentioned see app note 11 for details of this effect.
I have a query.
Can you please tell me can we use GPIO pins of DW1000 as output to send any kind of message?
I want to understand how much of the internal processor of UWB can i access?
There is no processor in the DW1000, at least not any conventional user accessible processor.
The GPIO lines each have a specific use, mostly indented for driving status LEDs, or can be user controlled / read over the SPI bus.
I suppose you could manually drive them in the correct way to output some sort of simple slow protocol but normally it would be far more sensible to do that from your processors own IO pins rather than by sending commands over SPI for a second device to change it’s IO pin state.
Thank you.
When i say processor, i mean the digital end of DW1000. I am interested to know the accessibility of that processor. Can i update the firmware on the DW1000?
for example, can i send a custom message from anchor to tag to turn on a LED connected to one of the GPIO of DW1000 without using host processor?