ADC and Teensy connection

[0822lyy]

I am working with ADC named ADS8568 and I ran into a problem.

I am using an Arduino Teensy 4.1 as interface between a PC and an ADS8568. ADC is in hardware and parallel mode. I am trying to get digital output of converted analog input of A0 channel. (Therefore, only channel A0 was connected and used, differing from the circuit diagram. Otherwise, such as references remain the same.)
The power connection was referenced from the ADC's datasheet (Typical Application, p.42), but I don't sure it is right.

I don't sure where is the problem lies whether in the software or the hardware. So the full circuit layout and datasheets are attached.

Also this is the Arduino code. I used direct register access, and the Teensy pin's GPIO(register) mapping is verified.

I use sine wave with an amplitude of 2.0V and applied it to the analog signal(A0).
The serial output is just 0 and I think the ADC is not working because BUSY signal is not working though CONVSTA signal is rising. I checked the input signals are go well in the ADC chip.

Thx for your help 

[moffy]

The level of ringing on the scope traces is horrendous, it's either a scope grounding issue or more likely due to the use of a breadboard and jumper leads. Can you make a prototype PCB to connect the Teensy to the ADC? The supplies and ground need solid connections.

[0822lyy]

The level of ringing on the scope traces is horrendous, it's either a scope grounding issue or more likely due to the use of a breadboard and jumper leads. Can you make a prototype PCB to connect the Teensy to the ADC? The supplies and ground need solid connections.

Thank you for the advice. The PCB is currently under delivering.
The CONVSTA occurs once every 5ms, and the oscilloscope image was observed in milliseconds. Therefore, it might have appeared that a significant amount of noise was present.
Could the noise potentially cause the ADC to stop functioning entirely?