What are the LPC553x Voltage Reference Selection Options?

[BrightFuture]

What are the LPC553x Voltage Reference Selection Options? I am referring specifically to the LPC5534JBD100K. 

LPC553x Reference Manual lists three options for REFSEL. What do these options correspond to?

Here is my assumption. Is this correct?
00 - Option 1 = Vref0 = VDDA
01 - Option 2 = Vref1 = VREF_OUT
10 - Option 3 = Vref2 = VREFP

Reference 1: "Figure 265. Analog subsystem connectivity" in the LPC553x Reference Manual.
Reference 2: REFSEL in the in the ADC Configuration Register (CFG)

Related post:
LPC553x number of usable external ADC channels

[xiangjun_rong]

Hi,

Pls refer to the ppt page screenshot.

CFG[REFSEL]=0, the ADC reference voltage is the external pad VREFP voltage.

CFG[REFSEL]=1, the ADC reference voltage is the VREF_OUT voltage, in the case, you have to initialize VREF_OUT module. Pls refer to Chapter 52 Voltage Reference (VREF)

CFG[REFSEL]=2, the ADC reference voltage is the VDDA pin power supply voltage.

Because the UM of LPC553x is not clear, per external customer requirement, I post it here.

BR

XiangJun Rong

[danielholala]

Sorry, your assumptions are incorrect. To quote the LPC553x reference manual:

[danielholala]

Just in case anybody thinks this is also true for DAC, don't be fooled, NXP wants us to read the manual properly. 

The DAC reference options "inverted", that is they are exactly as in @BrightFuture's  original posting:

It would have been too nice if there had been a pattern here regardings reference selection.

[_Leo_]

Thank you so much for your interest in our products and for using our community.

I noticed that you have another similar case, so I will follow up on this last one that I mention.

Have a nice day!