CDCE925: CDCE925 programming issue - please help

Yuval Izhaki

Prodigy 200 points

Part Number: CDCE925
Other Parts Discussed in Thread: CDCEL925, CLOCKPRO

Dear Sir \ Madam

In my design I am using the CDCE925 (1.8V out) for generating 5 system clock's,

Main system clock 8 Mhz (Y1) and 4 Ethernet clocks of 25Mhz each (Y2,3,4,5)

My clock source is 8 MHz LVCMOS oscillator connected to CDCE925 pin 1

I have used the TI clock pro V1.2 to define the registers values and my own hardware(STM32F4xx) to program the CDCE925 via I2C

I2C programming goes well and all byte received and acknowledged by the CDCE925 but there is no output coming from the CDCE925?

And all output tested high (no frequency output)

Below is the data byte sent to CDCE925 :

uint8_t const PllDataTable[49]={
                                    0x00,                                     // 1st byte is COMMAND CODE 0x00 "data block write"
                                    0x01,0x00,0xBC,0x19,0x02, // 5 data start here
                                    0x50,0x60,0x00,0x00,0x00, // 10
                                    0x00,0x00,0x00,0x00,0x00, // 15
                                    0x00,0x00,0x00,0x00,0x00, // 20
                                    0x6D,0x02,0x08,0x08,0xFE, // 25
                                    0xB0,0x03,0x23,0x00,0x40, // 30
                                    0x02,0x08,0x00,0x00,0x00,   // 35
                                    0x00,0x8D,0x02,0x08,0x08, // 40
                                    0x00,0x40,0x02,0x08,0x00, // 45
                                    0x40,0x02,0x08,                    // 50
                                 };

Please help,

Best regards,

Yuval Izhaki

over 7 years ago

0 Puneet Sareen over 7 years ago

TI__Expert 8865 points

Hello Yuval
Are you using CDCE925 or CDCEL925?
CDCE925 output supply spec is 2.5 to 3.3V!
Best regards
Puneet

0 Yuval Izhaki over 7 years ago in reply to Puneet Sareen

Prodigy 200 points

Puneet Sareen said:
Hello Yuval
Are you using CDCE925 or CDCEL925?
CDCE925 output supply spec is 2.5 to 3.3V!
Best regards
Puneet

Dear Puneet ,

Thank you for fast replay

I am using CDCEL925 IC

Best regards

Yuval

0 Yuval Izhaki over 7 years ago in reply to Yuval Izhaki

Prodigy 200 points

Hi all

Can any one please provide some help with this IC,

I think the problem is the hex code generated using the TI Software(TICLOCKPRO),

But I can't put my finger on the problem -since the design was fine and the upload to the chip was fine as well,

I am looking for an 8 MHz and 4 x 25 MHz clock outputs from this chip

Using 8MHz oscillator as input (1.8v Level)

Thank you

Yuval

0 Alan O over 7 years ago in reply to Yuval Izhaki

TI__Mastermind 32575 points

The S0 pin (multi-function input pin) can function as a output enable pin. Did you try changing S0 pin input state to see if the clock outputs are being gated off?

Alan

0 Alan O over 7 years ago in reply to Yuval Izhaki

TI__Mastermind 32575 points

Based on your configuration, I generated the ClockPro config file (.isf attached) and converted the registers (Bytes 0 to 47) to hex values as shown below.

There are several bytes that differ from the register values you had in your programming code.

Please try programming the hex values below to see if it resolves the issue, and also let S0 pin float high (internall pull-up) to ensure the outputs are not in HiZ state.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/48/CDCE925_5F00_E2Ea.HEX

0x01

0x08

0x34

0x01

0x02

0x50

0x60

0x00

0x5D

0x02

0x08

0x00

0x40

0x02

0x0B

0xFE

0xB0

0x03

0x20

0x00

0x8D

0x02

0x00

0x40

0x02

0x08

0xFF

0xA0

0x02

0x84

Regards,
Alan

0 Yacob Hassidim9 over 7 years ago in reply to Alan O

Prodigy 160 points

Hello Alan,

I am also interested on this issue.

I succeeded to download the *.HEX file but I don't see the *.isf file.

Can you please send again the *.isf file?

Thanks.
Yacob.

0 Alan O over 7 years ago in reply to Yacob Hassidim9

TI__Mastermind 32575 points

Please see attached.

Alan

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/48/CDCE925_5F00_E2Ea.ISF

0 Yacob Hassidim9 over 7 years ago in reply to Alan O

Prodigy 160 points

Thank you.

When I load your *.isf file I receive "Fvco Error" message. I pictured the message and save in Word file (attached).

Can you please advise me?

I hope the attaching has been succeeded. I used the "Insert File" from the menu to attach the file.

Is there other way to attach a file?

In case the attaching has not been succeeded, following is the message:

Fvco out of range (80MHz - 230 MHz) because Fin is not the one that generated this setup.

- Fvco-1 PLL 1 is out of range.

- Fvco-1 PLL 2 is out of range.

Sincerely,

Yacob Hassidim.

Fvco_Error_01.docx

0 Yuval Izhaki over 7 years ago in reply to Alan O

Prodigy 200 points

Dear Alan,

Thank you , very much for your help ,

I think the CDCE925 is working now , as I see some frequency coming out of the CDCE925 , output pin's ,

Best regards & happy Xmas

Yuval

0 Yacob Hassidim9 over 7 years ago in reply to Alan O

Prodigy 160 points

Hello Alan,

Thank you.

It works perfectly.

All the outputs generate the expected frequencies.

Sincerely,

Yacob.

Clock & timing

Clock & timing forum

CDCE925: CDCE925 programming issue - please help