We have developed our own DW100 based radio modules. They are used in conjunction with two different host platforms. The first host platform is based on TI’s MSP432 processor and the second is based on an Kinetis K60 processor running the MQX RTOS. On the K60 platform, the SPI baudrate is limited to approximately 5 MBd, data rates higher then 5 MBd generate errors on the SPI driver level. The K60 is supposed to run the responder code in the single-sided twr ranging setup. I got the example working with the reduced SPI speed on one side, by setting POLL_RX_TO_RESP_TX_DLY_UUS to 990 instead of 330. Of course, the ranging results I get are wrong. My question is, can I still make the example work with the reduced SPI speed on the responder side? Could you point me to the documentation explaining the mathematics of the delay value?
Thank you - Frank
Have a read of APS013 (DW1000 and two way ranging), and look at the diagrams of TWR exchange, this will show you how frame times/delays relate to particular channel/datarate/etc configuration.
You need to calculate the frame sizes/timings of your frames and see what delay will be sufficient
DW1000 DataSheet and User Manual have information regarding the various symbol timings.
thank you for your quick reply. I will read the recommended documents, in case I have still questions I will get back to you.
Thank you - Frank
Also please read the APS 022? It is about how to debug DW1000 applications.
Looking to your limitations of 5MHz, it is wrong that something fail, as dw1000 is working fine up to 20MHz
thank you for pointing me to the debug application note. The SPI speed problem is not coming from the DW1000, it comes from the host controller. This is why I need to change the timing of the ranging application to accommodate the required slower SPI communication.
Sincerely - Frank