After reading through this thread https://e2e.ti.com/support/microcontrollers/hercules/f/312/t/164919 I seem to be having a very similar issue.
The example project given in this thread helps to ensure the HTU is setup for single buffer implementation transferring data from the NHET to the CPU. I need to update instructions in the NHET so I'm focused on the CPU to NHET transfer and I have gotten this to work with a single buffer. My issue is that I can't get the Double Buffer mode to work for transfers from the CPU to the NHET. Based on the example project, I seem to have the setup correct but it still does not work. There seems to be little to no documentation on this specific mode and setting, namely Double Buffer mode transferring from CPU to NHET. I need to update more than 32 NHET instructions with one HTU request so it seemed like I should be able to do this with the double buffer mode.
The most helpful thing so far has been this app note: SPNA217. My project is similar in the sense that I am storing data in an array that the HTU can point to in order to update the NHET. The difference is I need to update multiple NHET instructions with one request so I need multiple elements in one frame where as this app note uses 1 element in multiple frames. I have also looked at the app note: SPNA130 and like the forum post I mentioned earlier says, it does not help as much since it is looking at the NHET to CPU transfer, not CPU to NHET.
To summarize, I am able to update the NHET from the CPU in Single Buffer mode. I am currently updating 22 instructions with one HTU request. However, I also need to be able to update 52 instructions as fast as possible. If the Double Buffer mode works the same way as when transferring from NHET to CPU, it appeared to double the buffer size so that would allow me to update 52 instructions with one HTU request. However, I cannot get this mode to work. I don't think I can use multiple frames either because it seemed like each frame points to the same initial NHET instruction so I would only be able to update the same 32 instructions when I actually need 52. I have also thought of using two DCP channels to split up the 52 instructions but at the moment I have no more DCP channels to spare.
What I would really like to know is: Can the HTU Double Buffer mode be used to transfer data from the CPU to the NHET? And will it allow me to transfer more than the maximum number of elements per frame (32)?
