We are evaluating the ATWINC1500 module. To make our life easier we connected an WINC1500-XPRO module to an SAMD21 X board and tried a couple of examples which went well. However, we could not use the debug UART on the module. We soldered the necessary 3 pins (GND, TX, RX) to J103 and connected to a CP2103 USB UART converter. According to the user guide of the module, we should be able to receive debug output with br 115200 8N1. Only garbage we could receive and we tried with 2 USB-UART converters. We even tried other common baud rates and settings but in vain. We have no idea how to proceed.
Please note that we were uploading some certs with the original example firmware upgrade application (code unmodified, only root certs were added).