good day guys,
From your guys suggestion, I decided to pull out the wiznet chip, but, Somehow my supervisor ask me to change to an i2c communication mode since many messy modification we need to work on for the SPI comm using Arduino Ethernet and EVAL-ADAU1701MINIZ . The current major problem is actually, MOSI signal voltage (from arduino) after go through diode 1N5822, seems suppressed by an EVAL-ADAU1701MINIZ circuit, once both SPI devices connected and powered. I can confirmed that suppression, by measuring using an oscilloscope and it gives me no signal but noise on ADAU1701 MOSI(CDATA) line.
I am going to zero again to start find out the appropriate circuit for connecting those I2C devices since both are operating in different voltage (3.3V and 5V).
Anyway, Thanks SurferTim and Riva for your help and hardworks. Insyaallah, Ill get back here once the project comes to SPI again...
thanks again.
thanks and Regards
kaeroul