Posts: 2
Registered: ‎03-21-2017

Si4735 CTSINT is missing

Hello all,


       I have ordered fresh chip and successfully got it connected to Arduino with 2-wire protocol I2C. Following carefully programming guide I powered up chip and got revision:


Final two digits of part number: 35
Firmware revision: 6.0
Component revision: 7.0
Chip revision: D


Next step I used is tune to frequency of 100Mhz and then I issue GET_INT_STATUS to wait for CTSINT interrupt to be set (0x81) as reply code. Doing it in cycle with 1sec delay I always got 0x80, but never 0x81


I did POWER_UP with the following arguments: ARG1 0xC0, ARG2 0x05

and I set only one property: GPO_IEN to 0xC9


What can be wrong?


PS: I have typical application schematic as mentioned at Si4730-31-34-35-D60_1.2.pdf.  Everything is assembled on the solderless breadboard except for the crystal that is hard-wired close to GP03 pin as suggested at AN383. When quartz was connected using external wires I did get 0x81 response very rarely, but chip works unstable - didn't get revision information often. So I consider it as a mistake.

Posts: 2
Registered: ‎03-21-2017

Re: Si4735 CTSINT is missing

I solved the problem by myself. AN322 example section was totally wrong. I copy-pasted example without verification.  According to the POWER_UP function description first argument must be 0x90 to enable external oscillator.