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Conversion delay
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Conversion delay

by Imsmooth on Thu Feb 27, 2014 10:17 pm

For the ads1015 and 1115 the conversion delays are

-----------------------------------------------------------------------*/
#define ADS1015_CONVERSIONDELAY (1)
#define ADS1115_CONVERSIONDELAY (8)
/*=========================================================================*/

This is from the library code which I am studying so I understand the operations properly.

Where in the Texas instrument PDF is this mentioned?
http://www.adafruit.com/datasheets/ads1115.pdf
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Re: Conversion delay

by adafruit_support_mike on Fri Feb 28, 2014 12:40 am

Those are derived values.

The ADS1x15 family of ADCs have an ALERT/READY pin that generates a pulse when each conversion is complete, but using that consumes a microcontroller pin and an interrupt service routine. Instead of using that, we wrote the library to wait for a fixed amount of time for the conversion to finish.

The ADS1015's maximum sampling rate is 3ksps, so a 1ms delay (corresponding to a rate of 1ksps) strikes a balance between simplicity and guaranteed success of getting a conversion. The ADS1115 can do 860sps, and our default delay takes the rate to 125sps.
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