2-DW3220 can't get the right POA after SYNC

Hi, everyone.
We are building a AOA localization system using 2 DW3220 ICs. To achieve this, one of the most important step is to get the 4 POA from the different antenna with this 2 DW3220. Just like the BETA_PODA_KIT which SYNC 2 DW1000 to get the 2 POA, we also need to SYNC our 2 DW3220. But something goes wrong.

The first picture is our designed board with 4 Uniform linear array(ULA). We put the tag right in front of it so that we can get almost the same POA from the 4 antenna if the SYNC is succeed. However, just like the second picture shows, PDOA from 2 ICs is right, RX time nearly the same(if not send the sync signal in code, the difference between the 2 RX time is huge). But we don’t get the POA wanted. The difference between the first two POA and the last two POA is still huge. Sometimes they are close, but this still happens without SYNC.
Here are our works. Firstly, we copied some of the design in BETA_PDOA_KIT, including the clock generation and SYNC signal synchronization circuit, logic code to control 2 DW ICs, SYNC\OSTR process. We also design a RC delay network to adjust the SYNC signal to meet the requirment in Datasheet and test it. The logic analyzer shows this:

So far, we still don’t find a solution. Is there anything we don’t notice?
Best Regard.

First, what PDoA Mode are you using, is it mode 1 or mode 3? And what length frames are you using?
Secondly, For each DW3000 chip, you should get a PDoA results that is equal to PoA1 - PoA2.
Have you confirmed that you can do that first?

Hi tiernanmc, I can’t get poa1 - poa2 == pdoa for one dw3220. What’s wrong with it?

What PDoA mode are you using? Mode 1 or mode 3?

mode3. In my program I use dwt_readdiagnostics() to get stsPOA, sts2POA and pdoa, but stsPOA - sts2POA sometimes close to pdoa while sometimes dose not.

I commented in your other post: