MSP430f5529 adc12

Nguyễn Huy

P6SEL |= BIT0 + BIT1;
ADC12CTL0 = ADC12ON+ADC12MSC+ADC12SHT0_8+ADC12REF2_5V+ADC12REFON; // Turn on ADC12, extend sampling time
                                            // to avoid overflow of results + V ref = 2.5V
ADC12CTL1 = ADC12SHP+ADC12CONSEQ_3;       // Use sampling timer, repeated sequence
ADC12MCTL0 = ADC12INCH_0;                 // ref+=AVcc = 2.5V, channel = A0
ADC12MCTL1 = ADC12INCH_1 + ADC12EOS;
ADC12IE = ADC12IE1;

I config adc12 for sequence multi channel

but it seem to be not right

I have 2.5 V in my channel but the result in adc < 0x800

Can any body help me

Thank you

over 8 years ago

0 Ryan Brown1 over 8 years ago

TI__Guru**** 219997 points

The REFMSTR bit of the REFCTL0 register is set by default, therefore the reference system is controlled by the REFCTL register instead of the ADC12_A module. You must therefore either reset this bit or set the REFVSEL_2 and REFON bits of REFCTL0. You also need to set the ADC12SREFx bits of the ADC12MCTLx register to set VREF+ as the voltage reference. Please refer to C examples MSP430F55xx_adc_06.c and MSP430F55xx_refctl_adc_02.c for further information.

Regards,
Ryan