Other Parts Discussed in Thread: MSP430F2274, CC2530
hello guys,
i have been working on the msp430f2274 zigbee kit for sometime now. I have downloaded the simple application from TI and have changed the getvcc3() as follows:
unsigned int getVcc3()
{
ADC10CTL0 = SREF_1 + REFON + REF2_5V + ADC10ON + ADC10SHT_3; // use internal ref, turn on 2.5V ref, set samp time = 64 cycles
ADC10CTL1 = INCH_4 ;
ADC10AE0 |= 0x10; // selecting channel A4
delayMs(1); // Allow internal reference to stabilize
ADC10CTL0 |= ENC + ADC10SC; // Enable conversions
while (!(ADC10CTL0 & ADC10IFG)); // Conversion done?
unsigned long temp = (ADC10MEM * 36000 ); // Convert raw ADC value to millivolts
return ((int) (temp / 10230));
}
with the above code i took the suggestion from this link: http://e2e.ti.com/support/low_power_rf/f/158/t/127604.aspx and used the math as per the link.
I was able to provide a square wave and obtained the output. but, the output was measuring 1.4v according to the adc converted results instead of 2v. I have connected to the pin no.7 on P2 of the target board.
what i do not understand is why is it 1.4 v instead of 2v.
here is the results obtained from the h-term.