Hi,
I am using ADS8634SRGER in my design and following is the block diagram of the design.
Test Procedure :
1. Using QT application, input the Voltage value on keyboard.
2. The Digital input is sent to DAC IC DAC7716SRHAR through SPI Interface from Processor (IC1).
3. The Analog outputs of DAC are routed to 2 row connector pins
4. Using Jumpers, the Analog signals are loopbacked and routed to ADC input.
5. ADC output connected to Processor (IC1) through SPI Interface,
6. Observe the valu on QT application display.
This design and test is working absolutely fine in my board.
But one observation was found while testing. If I remove the loopback Jumpers while testing and provide any input value on QT window (Step 1), I see som random readings on my QT window. This is not desirable behaviour for our application. We either want 0 or NO OUTPUT notice if no input is connected.
In other words, If input pins of ADC are floating I stii see some random readings at ADC output.
So please suggest us:
1. Whether there is any status register that indicates the absence of Input source. If yes, then how it can be communicated to Processor (IC1) ?
2. What will be ADC output in the absence of Input source (default condition).
Please help us in finding solution for this observation.
Regards,
Vijetha
