using FMC XM104

[ashwin_mendon]

Are there any example designs for programming the clock multipier chip Si5368 on the FMC XM104 daughter board using IIC? The user guide says that Si5368 does not provide any clocks to the board without first going through the internal register initialization process via IIC.

[eteam00]

The Si5368 has three versions:  A, B, and C.  You can download the datasheet for each version, plus the user manual, from here.  Strangely enough, the datasheets are not linked under the documentation tab, but under the 'product matrix' tab, and you will need to register with the website for access to the datasheets.

Here is a Si5368 datasheet which is freely accessible, but notice that it is marked 'preliminary'.

Needless to say, you shouldn't be using one of the Si5368-generated clocks to run your I2C interface to the Si5368 device.

-- Bob Elkind

[mahesh1359]

Refer http://www.xilinx.com/products/boards/v6conn/reference_designs.htm to find out some relevent reference designs

[ashwin_mendon]

There seems to be no reference designs for using the clocks that go through the clock circuits Si570 and Si5368. These need to be enabled via the I2C switch PCA9543 before they can be used.  The Si570 provides a default clock, but it runs at 156.25 MHZ. I need a 150 MHZ reference clock for SATA.

[eteam00 · Accepted solution]

There seems to be no reference designs for using the clocks that go through the clock circuits Si570 and Si5368. These need to be enabled via the I2C switch PCA9543 before they can be used.

If you are asking someone to write your code for you, that is not likely to happen.  Slightly less unlikely, but unlikely nonetheless, is example code for precisely your combination of development board plus add-on board.

There are four pieces of your design puzzle:

1. the capabilities of the Si5368
2. the required Si5368 register settings
3. Si5368 I2C interface address, commands, and timing
4. I2C master controller on the FPGA

The first 3 puzzle pieces are found in the Si5368 datasheet (see previous post in this thread).

The last piece, the I2C master controller logic, is not that difficult to design -- and there are plenty of source code examples for I2C masters.

What stops you from figuring out your own answers to your questions?

By the way, here's a web page I like to promote for FPGA and I2C newbies (with example code!).

The Si570 provides a default clock, but it runs at 156.25 MHZ.  I need a 150 MHZ reference clock for SATA.

Why not just wire up a 150MHz 4-pin CMOS oscillator?  Or use an on-chip (on the FPGA) PLL to reconstruct a 150MHz clock from of the board's standard reference clocks?  You haven't specified a development board or FPGA device, but most of the Virtex-6 dev boards include a 200MHz reference clock, from which it is rather simple to generate a 150MHz clock (multiply by 3 or 6 and divide by 4 or 8).

-- Bob Elkind