Facebook
Google
GitHub
Linkedin
Hi, I seem to be losing time in my ADCs. They should be taking 12*Tad = 7.5us but it's more like 10us. I have some simple code below that demonstrates the problem. Does anyone have any idea where the extra time is going and whether my sample point is being delayed or if the conversion is just taking longer than 12Tad? I've confirmed that the clock is running at 32MHz.
Code:
AD1CON3bits.ADCS = 9; // min.Tad = 600ns, 1FCY period = 62.5ns, therefore 10x = 625ns = 7.5us per 10bit conversion
AD1CON1bits.ADON = 0; // keep off
while(1)
{
__delay_ms(2);
AD1CON1bits.ADON = 0; // OFF
AD1CON3bits.SAMC = 0;
AD1CON1bits.SSRC = 0; // Manual sample control
AD1CHSbits.CH0SA = 2; // point muxA to AN2
AD1CON1bits.ADON = 1; // ON
AD1CON1bits.SAMP = 1;
__delay_us(2); // sufficient time to sample
PROBE1 = 1;
AD1CON1bits.SAMP = 0; // start conversion
while (!AD1CON1bits.DONE)
{
PROBE1 = 1;
PROBE1 = 0;
}
PROBE1 = 0;
}
Last edited:
