MangOH Yellow - UART1 / Cypress WiFi

Hi guys,

So I’m trying to talk to the IOT expander UART1, which seems to be /dev/ttyHS0. However, when I connect to pins 12 and 13 (TX and RX) on the IoT connector, I am unable to get the WiFi to start…

I receive a cryptic message:
Cypress chip MMC recognition may have been overwritten

And then it fails to start. Looking at the schematic, I don’t see that this UART is related to the WiFi in any way, or am I missing something?


If you are doing RX and TX loop back test, you can connect them through a series resistor (e.g. 100 Ohm) to get rid of the issue. It should not happen if you connect any IOT card though.