The GPIO 48 will be used as UART_TX when SPI interface is enabled in the code. (Though you are not going to use it anyway)
Please set useSpi = CyTrue; in CyU3PDeviceConfigureIOMatrix to enable SPI and that should help.
- Madhu Sudhan
Thanks for the information.
Turned out, just setting useSpi = CyTrue was not enough. In fact, when I did that, the FX3 would never come up after programming my firmware to RAM, or at least, it wouldn't enumerate. (I wonder why!)
When I also changed lppMode from UART_ONLY to DEFAULT, my firmware WOULD enumerate and now my UART output indeed goes to the 48 pin!
Then, just to check, with lppMode set to DEFAULT, I again changed useSpi back to CyFalse ... and I STILL got my UART output on pin 48, so apparently, it's the lpp mode, that determines the pin routing!
So far so good, but here's the question:
Is there any documentation of what these magic settings of the IoMatrix actually do, specifically with regards to routing pins.
I checked the API guide, the tech ref, the datasheet .. and I can't find any of this information!