I have the HL7800 version of the MangOH red. My serial ports will not work. I see 2 COM ports as described in step 10 of section 3.1 of HL78xx Getting Started Guide. One in the USB port and the other is the IoT card DB9 connection.
The USB console port continuously reads out a message about autoboot. The guide claims this port is not usable. The other COM port connected to the IoT card does nothing.
I could connect to the UART port (UART0) on the IO pins (CN307). This port will echo a few characters right at the beginning of the autoboot sequence. I cannot get any characters to echo through the IoT card (UART1).
I swapped out the provided HL7800 module for another one and I get the same behavior. The DIP switch has pins 1 and 4 ON. All others are off.