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LMX8410LEVM: LMX8410LEVM not possible to read the value of registers over SPI

Part Number: LMX8410LEVM
Other Parts Discussed in Thread: USB2ANY, LMX8410L

Dear community,
I am working with the board LMX8410LEVM and have to configurate the in an internal LO mode over SPI.
I see on the oscilloscope, that MOSI work, but MISO do not. All data on MISO are zero. When I try to read the default value of register, I receive only zeros on MISO canal.
I use the user guide, from to configure and to enable MUXout canal, register R0[2] = 0, to enable reading on MOXout(MISO) canal .
Can you tell me, what I do wrong?
Best Regards,
Iordan Pentchev.

  • Hi Pentchev,

    Did you mean you were not able to see anything in the oscilloscope from TP6? If MUXOUT is configured as Lock Detect output, will the LED light? 

  • Hi Noel Fung, thank you for the answear.
    I connect the oscilloscope to the
    TP7, TP8, TP9, and TP6 MUXout as MISO. I set R0[2]=0 as "Readback" to read back the MISO canal. I can see signals in the oscilloscope, but I can not read evary register, even when I have writen a value to this register. For example I can read registers R6 and R1, but I can not read R127, R44. And the Diode D1 is not ON when R0[2] is configured as "Lock Detect", the D1 is always OFF. In the user guid is not a description for all registers.

  • HI Iordan,

    The LED will light only when the synthesizer is locked and R0[2] is set to 1.

    All registers are readable, if you can read back one of those, you should be able to read all. Are you using USB2ANY to read / write the EVM?

  • Hi Noel Fung, thanks for the the answer.
    I am using SPI interface from another board, not the USB2ANY. I use MUXout TP and is set to R0[2=0 ], to read from LMX8410l, but I can read only some of the registers not all. What it is mean "synthesizer is locked"? Mean that the internal LO have to be locked, or in a working state?
    When R[0]=1, then it is not possible to readback from LMX8410l on the MISO canal? According the user guide must R[2]=0 to be possible to readback? I have install TSCS Pro and I want to configure the LMX8410l in internal LO mode. Can you tell me when I have configured the LMX8410l in internal LO mode with TSCS Pro, then it is possible to read read all registers values in TSCS Pro set for this mode?
    Best Regards,
    Iordan Penthev.

  • Hi Noel Fung,
    I want to ask you about "Recommended Initial Power Up Sequence" in the user guide page 30. What this mean "RESET = 1 to reset registers" and then "RESET = 0 to remove reset"? Where can I find this RESET Pin, ist this the "RESET_PLL" pin in R0 register? Do I have to set pin "FCAL_EN" in R0 register even in internal LO mode?
    Thank you!
    Best Regards,
    Iordan Pentchev.

  • Hi Iordan,

    R0[1] is the reset bit. If you program R0[1] = 1 once, all the registers will be reset to their silicon default values. 

    To read back written registers, we need to make MUXout pin = output serial data, so we need to make R0[2] = 0. To read back, we don't need to program all the registers in advance. After a Vcc power up, program R0[2] = 0. Then you can read back any register even though you did not program them, you will read back their silicon default value.

    If you have programmed the synthesizer (internal LO) to a certain frequency and it locks, then if MUXout is set to lock detect output (R0[2]=1), then you should be able to measure 3.3V at TP6 and the LED will light. 

    RESET = 1 means make R0[1] = 1. The device has internal power-on-reset (POR) feature, when Vcc is applied to the chip, the chip will reset itself. Since customer power supply could be very complex, sometime the Vcc ramp up edge is not sharp and as a result leading to POR failure. We recommend do a reset before programming the device. 

    I encourage you use TICS Pro to get familiar with the operation before moving to your own software. Have fun. 

  • R127 (INIT1)	0x7F0003
    R6 (INIT2)	0x060100
    R127	0x7F0000
    R126	0x7E0000
    R125	0x7D0000
    R124	0x7C0000
    R123	0x7B0000
    R122	0x7A0000
    R121	0x790000
    R120	0x780000
    R118	0x760000
    R117	0x750000
    R116	0x740000
    R115	0x730000
    R114	0x720000
    R113	0x710000
    R112	0x700000
    R111	0x6F0000
    R110	0x6E0000
    R109	0x6D0000
    R108	0x6C0000
    R107	0x6B0000
    R106	0x6A0000
    R103	0x670000
    R102	0x660000
    R101	0x650000
    R100	0x640000
    R99	0x630000
    R98	0x620000
    R97	0x610000
    R96	0x600000
    R95	0x5F0000
    R94	0x5E0000
    R93	0x5D0000
    R88	0x580000
    R87	0x570000
    R86	0x560000
    R85	0x550000
    R84	0x540000
    R83	0x530000
    R82	0x520000
    R81	0x510000
    R80	0x50000A
    R79	0x4F7000
    R78	0x4E0000
    R77	0x4D0000
    R76	0x4C0000
    R75	0x4B0000
    R74	0x4A0000
    R73	0x490000
    R72	0x480000
    R71	0x470000
    R70	0x460000
    R69	0x450000
    R68	0x440000
    R67	0x430000
    R66	0x420000
    R65	0x410000
    R64	0x400000
    R63	0x3F0000
    R62	0x3E0000
    R61	0x3D0000
    R60	0x3C0000
    R59	0x3B0000
    R58	0x3A0000
    R57	0x390000
    R56	0x380000
    R55	0x370000
    R54	0x360000
    R53	0x350000
    R52	0x340000
    R51	0x330000
    R50	0x320000
    R49	0x310000
    R48	0x300000
    R47	0x2F0000
    R46	0x2E0000
    R44	0x2C0080
    R43	0x2B0000
    R42	0x2A0000
    R41	0x290000
    R40	0x280000
    R39	0x270000
    R38	0x260000
    R37	0x250000
    R36	0x24005D
    R35	0x230000
    R34	0x220000
    R33	0x210000
    R32	0x200000
    R31	0x1F0000
    R30	0x1E0000
    R29	0x1D0000
    R28	0x1C0000
    R27	0x1B0000
    R26	0x1A0000
    R25	0x190000
    R24	0x180000
    R23	0x170000
    R22	0x160000
    R21	0x150000
    R19	0x130000
    R18	0x120000
    R17	0x110000
    R16	0x100000
    R15	0x0F0000
    R14	0x0E0070
    R13	0x0D0000
    R12	0x0C0000
    R11	0x0B0010
    R10	0x0A0080
    R9	0x090000
    R8	0x080000
    R7	0x070000
    R6	0x060000
    R5	0x050000
    R4	0x040000
    R3	0x030000
    R2	0x020000
    R1	0x010000
    R0	0x000004
    Hi Noel Fung,

    I have tried to set LMX8410l in internal LO mode, but the Diode is still not ON.

    I can send you my registers values. Can you please check where I have make mistakes by settings the values of the registers.
    Can you please send to me a example with internal LO by doing the Diode is ON(if you have one).

  • ok, I will check this out later.

  • Hi Noel Fung,
    I found in the Software a default configuration and with this configuration it works, the Diode is ON.
    Thank you for the support.
    Best Regards,
    Iordan Pentchev.

  • Hi Noel Fung,
    I have another question to you, how can I set in the registers a new frequency. I see in the TICS Pro where I can set a new frequency and the variable name  is "LO_FREQ", but I can not find this variable in the user guide. Can you say me please how can I set this frequency in the registers.
    Best Regards,
    Iordan Pentchev.

  • Hi Noel Fung,
    thank you very much for the support! Now it works well.
    Best Regards,
    Iordan Pentchev.

  • Hi Noel Fung,
    it works good now. I want to know it possible to change the output power of the LO signal? I which register can I change the output power, if this is possible? I did not find information in the user guide.
    Best regards,
    Iordan Pentchev.

  • Hi Iordan,

    Output power is not configurable.