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CDCE6214-Q1: OUT0 always high

Klaus Steinhammer
Prodigy 10 points
Part Number: CDCE6214-Q1

I am desperately trying to enable OUT0 on a CDCE6214-Q1, but did not succeed.

RefCLK is a 25MHz, 1.8V LVCOMS signal on PRIREF_P, output should be 100MHz LPHCSL signals on OUT2 and OUT3 and 25MHz, 1.8V LVCMOS signal on OUT0, IC is configured via I²C.

Output on OUT2 and OUT3 is working as expected, but OUT0 is always high.

For testing I configured OUT4 to output 25MHz, 1.8V LVCMOS which works as expected.

Can you please check the configuration below and point out the error to enable OUT0?

Thanks

Schematic:

TICS Pro Configuration:

Fullscreen CDCE6214TWRGExQ1 HexRegisterValues V0.2a.txt Download 
R85	0x00550000
R84	0x00540000
R83	0x00530000
R82	0x00520000
R81	0x00510004
R80	0x00500000
R79	0x004F0208
R78	0x004E1000
R77	0x004D0000
R76	0x004C0008
R75	0x004B6008
R74	0x004AA181
R73	0x00491000
R72	0x0048C001
R71	0x00470000
R70	0x00460008
R69	0x0045A181
R68	0x00443000
R67	0x00430006
R66	0x00420000
R65	0x00410008
R64	0x0040A181
R63	0x003F3000
R62	0x003E0006
R61	0x003D0000
R60	0x003C0008
R59	0x003B0008
R58	0x003A502C
R57	0x00395000
R56	0x00380006
R55	0x0037001E
R54	0x00363400
R53	0x00350069
R52	0x00345000
R51	0x003340C0
R50	0x003207C0
R49	0x00310013
R48	0x003023C7
R47	0x002F0380
R46	0x002E0000
R45	0x002D4F80
R44	0x002C0318
R43	0x002B0051
R42	0x002A0002
R41	0x00290000
R40	0x00280000
R39	0x00270000
R38	0x00260000
R37	0x00250000
R36	0x00240000
R35	0x00230000
R34	0x00220000
R33	0x00210000
R32	0x00200000
R31	0x001F0000
R30	0x001E0060
R29	0x001D0000
R28	0x001C0000
R27	0x001B0004
R26	0x001A0000
R25	0x00194401
R24	0x00180024
R23	0x00170000
R22	0x00160000
R21	0x00150000
R20	0x00140000
R19	0x00130000
R18	0x00120000
R17	0x001126C4
R16	0x0010921F
R15	0x000FA037
R14	0x000E0000
R13	0x000D0000
R12	0x000C0000
R11	0x000B0000
R10	0x000A0000
R9	0x00090000
R8	0x00080000
R7	0x00070C0D
R6	0x00060000
R5	0x00050000
R4	0x00040000
R3	0x00030000
R2	0x00020003
R1	0x00012310
R0	0x00003010

  • 0
    TI__Mastermind 18225 points

    Hi Klaus,

    I looked at your configuration and it appears that all of the registers for OUT0 have been set correctly, so I wonder if the problem is related to the board. Is there a difference in termination between OUT0 and OUT4?

    Best,

    Evan Su

  • 0 in reply to Evan Su
    Prodigy 20 points

    Hi Evan,

    thanks for your answer.

    in our design the total length of the OUT0 is <15mm with an input capacitance of 1pF according datasheet and the 10ohm close to source

    OUT4 is left unconnected

  • 0 in reply to Philipp Schirg
    TI__Mastermind 18225 points

    Hi Philipp,

    When OUT4 was configured to 25 MHz LVCMOS for testing and the operation was verified, what was the measurement method? Was OUT4 connected directly to a probe for example? I am trying to think of possible hardware causes, on the schematic the only difference I can see between OUT0 and the other outputs is the series resistor.

    Next week I will try to find time to load the configuration on my CDCE6214-Q1 EVM and see if I can replicate the issue, which would help confirm if it is a chip issue or not.

    Thanks,

    Evan Su

  • 0 in reply to Evan Su
    TI__Mastermind 22140 points

    Philipp,

    With the resistor after OUT0 depopulated, is there still only a high level at the pin?
    Want to ensure that the issue is solely from the clock gen.

    Thanks,

    Kadeem

  • 0
    Prodigy 20 points

    Hi Evan & Kadeem,

    we did not test to remove the R on OUT0 but found out, that with a pullup on HW_SW_CTRL (selecting EEPROM page one) it works fine.

    After configuration via I2C there is a 25MHz output also on OUT0!

    Following questions appear now:

    a) Is it a wrong (or illegal) state to have HW_SW_CTRL floating and REFSEL pulled up?
    For Fall-back mode both have to be floating?
    The I2C slave address still was 68h and not 67h as in Fall-back mode

    b) When reading back the values we write to the chip we still get differences although it seems to work as described above:

    Difference found at register 0x52. Written: 0x0000, Read: 0x00ff
    Difference found at register 0x51. Written: 0x0004, Read: 0xc001
    Difference found at register 0x50. Written: 0x0000, Read: 0x0400
    Difference found at register 0x4f. Written: 0x0208, Read: 0x0000
    Difference found at register 0x4e. Written: 0x1000, Read: 0x0802
    Difference found at register 0x4d. Written: 0x0000, Read: 0x0010
    Difference found at register 0x4c. Written: 0x0008, Read: 0x0000
    Difference found at register 0x4b. Written: 0x6008, Read: 0x0800
    Difference found at register 0x4a. Written: 0xa181, Read: 0x0860
    Difference found at register 0x49. Written: 0x1000, Read: 0x81a1
    Difference found at register 0x48. Written: 0xc001, Read: 0x0010
    Difference found at register 0x47. Written: 0x0000, Read: 0x01c0
    Difference found at register 0x46. Written: 0x0008, Read: 0x0000
    Difference found at register 0x45. Written: 0xa181, Read: 0x0800
    Difference found at register 0x44. Written: 0x3000, Read: 0x81a1
    Difference found at register 0x43. Written: 0x0006, Read: 0x0030
    Difference found at register 0x42. Written: 0x0000, Read: 0x0600
    Difference found at register 0x41. Written: 0x0008, Read: 0x0000
    Difference found at register 0x40. Written: 0xa181, Read: 0x0800
    Difference found at register 0x3f. Written: 0x3000, Read: 0x81a1
    Difference found at register 0x3e. Written: 0x0006, Read: 0x0030
    Difference found at register 0x3d. Written: 0x0000, Read: 0x0600
    Difference found at register 0x3c. Written: 0x0008, Read: 0x0000
    Difference found at register 0x3b. Written: 0x0008, Read: 0x0800
    Difference found at register 0x3a. Written: 0x502c, Read: 0x0800
    Difference found at register 0x39. Written: 0x5000, Read: 0x2c50
    Difference found at register 0x38. Written: 0x0006, Read: 0x0050
    Difference found at register 0x37. Written: 0x001e, Read: 0x0600
    Difference found at register 0x36. Written: 0x3400, Read: 0x1e00
    Difference found at register 0x35. Written: 0x0069, Read: 0x0034
    Difference found at register 0x34. Written: 0x5000, Read: 0x6900
    Difference found at register 0x33. Written: 0x40c0, Read: 0x0050
    Difference found at register 0x32. Written: 0x07c0, Read: 0xc040
    Difference found at register 0x31. Written: 0x0013, Read: 0xc007
    Difference found at register 0x30. Written: 0x23c7, Read: 0x1300
    Difference found at register 0x2f. Written: 0x0380, Read: 0xc723
    Difference found at register 0x2e. Written: 0x0000, Read: 0x8003
    Difference found at register 0x2d. Written: 0x4f80, Read: 0x0000
    Difference found at register 0x2c. Written: 0x0318, Read: 0x804f
    Difference found at register 0x2b. Written: 0x0051, Read: 0x1803
    Difference found at register 0x2a. Written: 0x0002, Read: 0x5100
    Difference found at register 0x29. Written: 0x0000, Read: 0x0200
    Difference found at register 0x22. Written: 0x0000, Read: 0x2800
    Difference found at register 0x1e. Written: 0x0060, Read: 0x0000
    Difference found at register 0x1d. Written: 0x0000, Read: 0x6000
    Difference found at register 0x1b. Written: 0x0004, Read: 0x0000
    Difference found at register 0x1a. Written: 0x0000, Read: 0x0400
    Difference found at register 0x19. Written: 0x4401, Read: 0x0000
    Difference found at register 0x18. Written: 0x0024, Read: 0x0144
    Difference found at register 0x17. Written: 0x0000, Read: 0x2400
    Difference found at register 0x16. Written: 0x0000, Read: 0x0624
    Difference found at register 0x15. Written: 0x0000, Read: 0xa200
    Difference found at register 0x14. Written: 0x0000, Read: 0x1f05
    Difference found at register 0x11. Written: 0x26c4, Read: 0x0000
    Difference found at register 0x10. Written: 0x921f, Read: 0xc426
    Difference found at register 0x0f. Written: 0xa037, Read: 0x1f92
    Difference found at register 0x0e. Written: 0x0000, Read: 0x37a0
    Difference found at register 0x0b. Written: 0x0000, Read: 0x0270
    Difference found at register 0x08. Written: 0x0000, Read: 0x9b2e
    Difference found at register 0x07. Written: 0x0c0d, Read: 0x0100
    Difference found at register 0x06. Written: 0x0000, Read: 0xac04
    Difference found at register 0x05. Written: 0x0000, Read: 0xec0e
    Difference found at register 0x02. Written: 0x0003, Read: 0x0000
    Difference found at register 0x01. Written: 0x2310, Read: 0x0300
    Difference found at register 0x00. Written: 0x3010, Read: 0x1023

    Thanks,

    Philipp

  • 0 in reply to Philipp Schirg
    TI__Mastermind 22140 points

    Philipp,

    I do advise using either a pull-down or pull-up resistor on the HW_SW_CTRL pin for selecting one of the two EEPROM pages for storing configurations to load on power-up. Fall-back mode requires both HW_SW_CTRL and REF_SEL to be floating.

    It does not make sense that the readback is different, especially when considering that ch0_en must be set in order for OUT0 to be active. Are there any other devices on the bus that may be getting read from instead of this one? Is this behavior still observed after a power cycle?
    Thanks,

    Kadeem