I decided to measure the internal temperature of AD7175-2 chip on the second channel. The chip is initialized to measure two channels:
- Channel0: Voltage between AIN0+ and AIN0- (Command 0x10 0x8001)
- Channel1: Voltage on internal temperature sensor. (Command 0x11 0x8232)
- Channel3 and 4 are disabled.
- Both channels uses the Setup0 register (Command: 0x20 0x0320)
I use the Single Conversion mode. The data sheet says on page 41:
“…As soon as the conversion is available, the RDY output goes low. The ADC then selects the next channel and begins a conversion…”
But there is no second conversion. The channel0 is converted but even the application waits almost three times more (158µs ) than the first conversion time (41µs) the DOUT/RDY pin stays high and never goes low. What do I do wrong?
- Yellow: Chip select of AD7175-2
- Green: Data input of AD7175-2
- Pink: Data output/ Data Ready of AD7175-2
- Blue: Serial clock.
My other notice is. On page 48. Internal Temperature sensor chapter the nominal sensitivity in the text is 470µV/K but in the temperature calculation it is 477µV/K. Which is right? The manual says the temperature in °C = (Conversion Result / 477µV) – 273.15. But the Conversion Result is not the code I read from the converter. First it must be converted to voltage, is not it? Using “Conversion Result” is very confusing.
Thank you for your help!
Wrong part number in title. I am sorry...
[edited by: Louie88 at 7:44 AM (GMT -5) on 6 Jan 2022]