Posts: 1
Registered: ‎02-22-2017

Si5344 Rev D SPI programming

We are trying to program the Si5344 by external SPI master. The register values are generated by Clock builder Pro 2.12.1. It seems like the SPI is working but we don't see any output on the OUT pins.
- SPI read writes were tested by doing multiple read/write on Scratch area 0x026B-0x0272. We are confident that SPI is working.
- We are writing only the sequence generated by the clock builder exported C header.
- We have enabled the Preamble and post-amble.
- We also tried adding some delay after preamble write as per datasheet.
- One difference we noticed is:
   - Data sheet for Rev-D has R0_REG-R3-REG address as 0x024A-0x024C and Clock builder generates the addresses as 0x0250-0x025F. I dont know which one should be correct. I tried both and did not see any difference.
- Is there some timing synchronization required between subsequent writes of large modification.
- We read back all the values set during write modification and those seems to be correct. (except few of them return different which are write on clear type registers). 
- Outputs are enabled.
- We are connecting external SPI master to the Si5344 -EVB(SPI header on DUT side). The EVB works fine if we program it by clockbuilder directly by USB and fails if we try external SPI master writing the exported values.

- We are using it in free running mode.

Any suggestion or anything else we need to update/modify.