ADS1261: Conversion start condition

user4863760

Part Number: ADS1261

Hello,

Recently I'm using ADS1261. The conversion mode is set to "pulse-conversion". I can get proper conversion result through SPI commands "Start conversion(08h)". Everything is fine. But there's one thing I can't understand. Each time before I perform a pulse mode conversion, I always need to rewrite the "INPMUX" register. I thought the input multiplexer should have been set up correctly at power-on reset. Did I miss something about ADC configuration?

over 5 years ago

0 Bryan Lizon86 over 5 years ago

TI__Guru 55591 points

Hi User,

You should not need to rewrite the input mux register each time you convert. Can you help me understand why you do this? What happens if you do not?

-Bryan

0 user4863760 over 5 years ago in reply to Bryan Lizon86

Prodigy 30 points

Hello Bryan,

If I don't rewrite "INPMUX" register, the conversion won't start. At first, four sensors were connected to the inputs. I query each of the four input pair in turn. So rewriting "INPMUX" register is necessary. Once I removed three sensors, the conversion wouldn't start if I didn't rewrite the "INPMUX" register. This is the reason why I'm still rewrite "INPMUX" register now. That's why I'm curious. I found this problem accidently. Maybe there's something wrong with my configuration. So let me list the settings of my application below:

The following is the ADC configuration chart:

The following is the SPI settings:

The following is the NVIC of my firmware(the lowest number represents the highest interrupt priority)

0 Bryan Lizon86 over 5 years ago in reply to user4863760

TI__Guru 55591 points

Hi User,

If you did not use INPMUX to start conversions, how would you control conversions then? Are you issuing the START command or pulling the START pin high? If so, what happens when you do this?

If you are issuing the START command, please send me logic analyzer shots of the DIN and DOUT pins.

-Bryan