Hi @scosgrove,

Thanks for the details.

On the DSP there is a dedicated HW block for each UART (similar for the UARTs connected to the application processor). All the UARTs supported on DSP have hardware FIFOs. Since you asked about the size:

DSP UART2 has 64-byte low level FIFO on RX DSP UART6, 7 have 128-byte low level FIFO on RX

When fifo is close to filling up, there is an ISR that triggers on the DSP which transfers the data from FIFO to other memory, and then the data propagates to the user. I wonder if there is some issue when fifo is read while another byte is incoming into fifo at the same time.

Which uart port are you using for this test?

I can do some testing with bursts of 70-250 byte packets. In the past we have tested continuous data transfers of several KB but not at high rates. Also, what baud rate are you using now?

Alex

Answers to some of your questions:

The VOXL is meant to be a flexible development platform that allows developers to choose where best to run the components of their application. There is documentation describing various CPU and DSP development paradigms. The GPU is typically accessed via OpenCL and OpenGL. In general, the CPU is used for most things, the "sensors DSP" (aka SLPI, SDSP) runs the flight controller (SNAV, PX4 in the near future), and the GPU offloads certain OpenCV or other applications via OpenCL / OpenGL. The "applications DSP" (aka ADSP) is not really used for anything right now but is accessible. There is also a hardware video accelerator known as "Venus" that can offload certain tasks via OpenMAX.

There is flexibility with how sensors are attached to the system. Cameras primarily come in via the MIPI connectors. Each camera, however, requires custom support. There are some supported "out of the box" (eg OV7251, IMX214, etc.), while new ones would have to be developed. Cameras can also come in via USB using UVC. There are IMUs on the VOXL that can be accessed directly via the SDSP. There is GPS capability directly on VOXL (See the GPS antenna connector) that can be accessed via SNAV or else an external GPS unit can be attached via the J7 connector. There are other lots of other options as well depending on the application.

Load on CPU and GPU can be monitored using our voxl-perfmon python script (https://gitlab.com/voxl-public/voxl-utils/-/blob/master/bin/voxl-perfmon). We will add DSP to this as well.