Hi,
We've been having problems trying to implement a high-speed uart communication between the nRF52832 and an STM32.
We switched to using libuarte so we can use DMA even though our communication protocol has variable-sized packets Unfortunately, after several seconds of working perfectly, we suddenly start seeing errors. In between good new data blocks, we suddenly have one block that has old data. So either the data was never written by DMA, or it was written somewhere other than we are told to read from. It was only for the amount of data that the NRF_LIBUARTE_ASYNC_EVT_RX_DATA reported. It seemed kinda like the timeout triggered before the data was actually copied by the DMA or something along those lines.
We've reduced the transmission speed to 115200, and the error still occurs. We've used a logic analyzer to check if the data is really being transferred - it definitely is, but the nordic is not getting it. We've tried it with SDK 15.0, 15.3 and 16.0, the problem remains.
Since our codebase is way too complex to try and post something helpful here, we tried recreating the issue with two nRF52840 DKs.
Unfortunately, we're not getting the same errors, but are getting another error in the first RX event. First, right after we initialize libuarte_async we get NRF_LIBUARTE_ASYNC_EVT_ERROR errorSrc 0 - this started with SDK 16.0, it wasn't occurring when using SDK 15.x with ported libuarte. Then we get a bunch of skipped bytes reported (check the attached project):<info> app: Rx 128@x20004B84<error> app: RX: expected x65, got x39 instead<error> app: RX: expected x3A, got x3D instead<error> app: RX: expected x3E, got x41 instead<error> app: RX: expected x42, got x45 instead<error> app: RX: expected x46, got x49 instead<error> app: RX: expected x4A, got x4D instead
Note: We're using arm-none-eabi-gcc v4.9.3 to build it the test project, targeting nrf52840 chip sitting on development kits. They are connected and both running the same firmware, both doing RX and TX using libuarte.
