HSADC on LPC4370 question

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by JohnR on Wed Apr 23 18:15:30 MST 2014
hi All,

What are the settings to allow the 12-bit HSADC in LPC4370 to generate a 0 - 4095 straight binary output for a unipolar input on, say ADCHS_0, from an input voltage of 0 to 1.2 volts approx.

At the present I have grounded ADCHS_NEG and tried different combinations of the DCINNEG and DCINPOS settings but I seem to get only half of the range.

For instance, with DCINNEG and DCINPOS both equal to HSADC_CHANNEL_NODCBIAS (0) and TWOS set to offset binary, an input range of 0.05 to .40 volts gives output values from 2148 to 3840 counts.

I think I may have to remove the ground on ADCHS_NEG so it floats and set DCINNEG = 1.

Could someone let me know that this is right.

Thanks in advance,