I wonder what do this line mean?
// ... If A0 > 0.5*AVcc, P1.0 set, else reset.
-- OCY
--- In m..., "hragsarkissian" wrote:
>
> Hi,
>
> I am trying this sample code.
>
//******************************************************************************
> // MSP430F21x2 Demo - ADC10, Sample A0, AVcc Ref, Set P1.0 if A0 >
0.5*AVcc
> //
> // Description: A single sample is made on A0 with reference to AVcc.
> // Software sets ADC10SC to start sample and conversion - ADC10SC
> // automatically cleared at EOC. ADC10 internal oscillator times sample
(16x)
> // and conversion. In Mainloop MSP430 waits in LPM0 to save power until
ADC10
> // conversion complete, ADC10_ISR will force exit from LPM0 in Mainloop on
> // reti. If A0 > 0.5*AVcc, P1.0 set, else reset.
> //
> // MSP430F21x2
> // -----------------
> // /|\| XIN|-
> // | | |
> // --|RST XOUT|-
> // | |
> // >---|P2.0/A0 P1.0|-->LED
> //
> // A. Dannenberg
> // Texas Instruments Inc.
> // December 2007
> // Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.41A
>
//******************************************************************************
> #include "msp430x21x2.h"
>
> void main(void)
> {
> WDTCTL = WDTPW + WDTHOLD; // Stop WDT
> ADC10CTL0 = ADC10SHT_2 + ADC10ON + ADC10IE; // ADC10ON, interrupt enabled
> ADC10AE0 |= 0x01; // P2.0 ADC option select
>
> P1DIR |= 0x01; // Set P1.0 to output direction
>
> for (;;)
> {
> ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion
start
> __bis_SR_register(CPUOFF + GIE); // LPM0, ADC10_ISR will force
exit
> if (ADC10MEM < 0x1FF)
> P1OUT &= ~0x01; // Clear P1.0 LED off
> else
> P1OUT |= 0x01; // Set P1.0 LED on
> }
>
> I would like to change the voltage threshold which im assuming is 0x1FF.
However, Im having trouble understanding how these hex values work.
> Could someone please explain what 0x1FF means and what it could be changed
to.
>