Well, I just started to explore the ADC example of https://www.nxp.com/downloads/en/software/LPC845BRK_Examples.zip (LPC845_ADC_LDR).
The function BOARD_InitPins() in pin_mux.c contains:
As you can see in the last 2 lines, USART0_TXD and USART0_RXD are configured.
Why line 1, 2 and 4 are here? Are they to trigger a conversion? Then this information is missed in the introductory description of the application (but I may be wrong because I'm very tired today).
When I switch to the Pins tool and the mex-file is loaded, this pin_mux.c differs. Here the USART0 e.g. is not configured:
And why ADC_CHN0 is configured? I think it's fixed to the potentiometer.