cannot communicate with SC16IS750 over SPI

[Nishihashi]

Hi.

I am currently trying to communicate with SC16IS750 over SPI.
I checked RESET signal was H-level, and CPU sent SPI mode 0 signal as following:

This is a waveform on reading RXLVL register at the time of release reset.
I expected to receive 0, but the result was different.

I additionaly checked:

• Direct connection (MISO/MOSI/CLK etc)
• 3.3V power
• Reset is released
• SPI translation rate is 3.125Mbps

Do I have something wrong?

Thanks in advance.

[guoweisun · Accepted solution]

HI

Please see comment:

1: Please refer to hardware schematic.

2:Read the detail SPI specification on datasheet page51 and follow this timing on operate SPI.