Search FAQs on the left to see if your question has been answered. Click on the dropdown to view all of the documents associated with the product. If you can't find your question, click on Ask a Question.
I have a question about the timing of AD7799. The Datasheet says "Ready Bit. Cleared when data is written to the data register. Set after the data register is read or after a period of time before the data register is updated with a new conversion result to indicate to the user not to read the conversion data. It is also set when the part is placed in power-down mode. The end of a conversion is indicated by the DOUT/RDY pin. This pin can be used as an alternative to the status register for monitoring the ADC for conversion data." So I want to know the exactly how much time is that period? And if I check the /RDY pin, it will goes high after a period of time before the data register is updated with a new conversion result, it is the same as /RDY bit, Then how long is this period? In other word, it will tell me how much time left at least for me to read the data.
The DRDY pin goes low when a new conversion is available. If the customer reads the conversion, DRDY will go high as soon as the data register is read. The customer can read the data register even when DRDY is high as it will not be updated until the next conversion is available. If the customer does not read the conversion, then DRDY stays low indicating that a valid conversion is available. However, when the next conversion is available, DRDY goes high when the data register is being updated. DRDY goes high for 0.8 ms approximately. The customer should not read the data register during this period as it will not contain a valid conversion (it will be in a transient state). So, in summary, the customer has a time of 1/Fadc - 0.8 ms typically to read the data register after the DRDY high to low transition occurs (Fadc = update rate selected).