I have set ADC to work in sync mode, enabled clock, peripheral, VREF, VDDA in SYSCON. Set the pin to analog. I am using single step conversion with setting start bit in CTRL.
While my oscilloscope is showing different voltages from input on ADC0, my ADC reads almost the same value all the time, 0xfec.
I have ran the calibration upon initialisation. Do I need to do anything with that value ?
setup:
m_port = LPC_ADC;
m_pin = a_pin;
LPC_SYSCON->PDRUNCFGCLR |= (1<<10);
LPC_SYSCON->PDRUNCFGCLR |= (1<<19) | (1<<23); //VDDA ad VREF
LPC_SYSCON->AHBCLKCTRLSET[0] |= (1<<27) | (1<<13); //adc and iocon
LPC_SYSCON->PRESETCTRLCLR[0] |= (1<<27) | (1<<13);
LPC_SYSCON->ADCCLKDIV = 0x01; //clock divider
m_port->CTRL |= (1<<0);
LPC_IOCON->PIO[0][29] = 0x120; //ADC_0, analog, filter off, invert disabled, mode inactive, od normal.
m_port->CTRL &= ~(1<<8); //sync mode
m_port->CTRL &= ~(0x3<<9); //clear res
m_port->CTRL |= (0x02<<9); //10-bit res
m_port->SEQ_CTRL[0] &= ~_BV(31); //disable ADC
m_port->SEQ_CTRL[0] |= _BV(18); //TrigPolarity
m_port->SEQ_CTRL[0] |= _BV(31); //enable ADC
m_port->STARTUP = 1;
m_port->CALIBR |= (1<<0); //start calibration
while(IS_BIT_ENABLED(m_port->CALIBR, 0));
Read:
unsigned long timeout=1000;
m_port->SEQ_CTRL[0] |= _BV(m_pin); //enable ADC channel
m_port->SEQ_CTRL[0] |= _BV(28);
m_port->SEQ_CTRL[0] |= _BV(26);
while (!IS_BIT_ENABLED(m_port->DAT[m_pin], 31)) //wait until end of conversion
{ if (--timeout == 0) return 0; }
m_port->SEQ_CTRL[0] &= ~_BV(26);
return (m_port->DAT[m_pin] >> 4) & 0xfff;
I am using OM13077. VREFP is 3.3v, VREFN is gnd. Internal RC clock is used.
Am i missing something ?
