• State
  • Locked Locked
  • Replies 7 replies
  • Subscribers 22 subscribers
  • Views 393 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

LMK04828: LMK04828 Register Configuration Issue

LMK04821: LMK04821 Lock issue

Enhui Yang
Expert 3240 points

Part Number: LMK04821
Other Parts Discussed in Thread: LMK04828

Hi team,

We use LMK04821 find this device can lock when the register 0x144 is FF, but when it is 0x00 is unlock. Could you provide some suggestions? Thanks.

  • 0
    TI__Mastermind 19551 points

    Hi Enhui, 

    This bug should be solvable by setting the SYNC_1SHOT_EN bit to 1 if you want your SYNC_DISx bits to be set to 0. Doing so makes the SYNC pin edge sensitive, rather than level sensitive. 

    I typically encounter this bug in ZDM (this is an assumption on my part but it makes sense that this would be seen if the output divider is in your feedback path) due to the SYNC condition not being cleared - which holds the divider in reset and prevents lock. Setting SYNC_1SHOT_EN will automatically clear the SYNC condition following a rising edge, and should result in lock.

    Thanks,

    Michael

  • 0 in reply to Michael Srinivasan
    TI__Expert 3240 points

    Hi Michael,

    Thanks for your suggestion, they can use this method to lock. However, the synchronization issue still cannot be resolved. Currently, their configuration allows an integer N/R division ratio, and the input reference clock (OSCin), DCLKout8, and sysref clock all have a multiple relationship. Additionally, they found that when reading back register 0x144, no matter what value they ultimately configure, the read-back register value is 0x00. Could you provide some suggestions? Thanks.

  • 0 in reply to Enhui Yang
    TI__Mastermind 19551 points

    Hi Enhui,

    Can you provide the customer's configuration?

    Thanks,

    Michael

  • 0 in reply to Michael Srinivasan
    TI__Expert 3240 points

    Hi Michael,

    Please find configuration as below. Thanks.

    Fullscreen 10in_4_92g_rb410_20251029Mhz.txt Download 
    R0 (INIT)	0x000090
R0	0x000010
R2	0x000200
R3	0x000306
R4	0x0004D0
R5	0x00055B
R6	0x000600
R12	0x000C51
R13	0x000D04
R256	0x010014
R257	0x010155
R258	0x010255
R259	0x010301
R260	0x010422
R261	0x010500
R262	0x010670
R263	0x010766
R264	0x010814
R265	0x010955
R266	0x010A55
R267	0x010B01
R268	0x010C22
R269	0x010D00
R270	0x010E70
R271	0x010F66
R272	0x011006
R273	0x011155
R274	0x011255
R275	0x011301
R276	0x011422
R277	0x011500
R278	0x011670
R279	0x011760
R280	0x011806
R281	0x011955
R282	0x011A55
R283	0x011B01
R284	0x011C22
R285	0x011D00
R286	0x011E70
R287	0x011F10
R288	0x012006
R289	0x012155
R290	0x012255
R291	0x012301
R292	0x012422
R293	0x012500
R294	0x012670
R295	0x012713
R296	0x012806
R297	0x012955
R298	0x012A55
R299	0x012B01
R300	0x012C22
R301	0x012D00
R302	0x012E70
R303	0x012F60
R304	0x013006
R305	0x013155
R306	0x013255
R307	0x013301
R308	0x013422
R309	0x013500
R310	0x013671
R311	0x013701
R312	0x013800
R313	0x013903
R314	0x013A01
R315	0x013BEC
R316	0x013C00
R317	0x013D08
R318	0x013E01
R319	0x013F13
R320	0x014081
R321	0x014100
R322	0x014200
R323	0x014351
R324	0x0144C3
R325	0x01457F
R326	0x014600
R327	0x01471F
R328	0x014802
R329	0x014942
R330	0x014A02
R331	0x014B16
R332	0x014C00
R333	0x014D00
R334	0x014EC0
R335	0x014F7F
R336	0x015003
R337	0x015102
R338	0x015200
R339	0x015300
R340	0x015478
R341	0x015500
R342	0x015678
R343	0x015700
R344	0x015896
R345	0x015900
R346	0x015A78
R347	0x015BD4
R348	0x015C20
R349	0x015D00
R350	0x015E00
R351	0x015F0B
R352	0x016000
R353	0x016101
R354	0x016224
R355	0x016300
R356	0x016400
R357	0x01657B
R369	0x0171AA
R370	0x017202
R380	0x017C15
R381	0x017D33
R358	0x016600
R359	0x016700
R360	0x016829
R361	0x016959
R362	0x016A20
R363	0x016B00
R364	0x016C00
R365	0x016D00
R366	0x016E13
R371	0x017300
R386	0x018200
R387	0x018300
R388	0x018400
R389	0x018500
R392	0x018800
R393	0x018900
R394	0x018A00
R395	0x018B00
R8189	0x1FFD00
R8190	0x1FFE00
R8191	0x1FFF53
    10in_4_92g_rb410_20251029Mhz.tcs
    Fullscreen 47DR回读错误寄存器.txt Download 
    寄存器写入   回读
0x0004 D0 >>10   only R
0x0006 00 >>20	 only R
0x0140 81>>01
0x0144 FF >>03
0x014E C0 >>00
0x0158 96 >>16 

锁定状态 可以忽略
0x0183 00 >>02   
0x0184 00 >>10	
0x0189 00 >> 0C   
0x018B 00 >> 10
0x1FFFF 53 >> 00

  • 0 in reply to Enhui Yang
    TI__Mastermind 19551 points

    Hi Enhui,

    The issues being seen are likely due to the VCO setting of 2460MHz. That is outside of the supported VCO range for this device. VCO0 supports 1930-2075MHz, while VCO1 supports 2920-3080MHz. It is difficult for me to rework this given your output frequency constraints. 

    Is there anyway the output frequencies could be altered in a way such their their least common multiple falls into these ranges?

    Thanks.

    Michael

  • 0 in reply to Michael Srinivasan
    TI__Expert 3240 points

    Hi Michael,

    They use LMK04828, VCO0 frequency is 2370 to 2630 MHz.

  • 0 in reply to Enhui Yang
    TI__Mastermind 19551 points

    Hi Enhui,

    Thank you for clarifying that. How is the customer triggering their SYNC event? Can they try doing so with the configuration I have created? I am just curious if there is something set that I am not aware of in the configuration you shared with me.

    lmk04828_test.tcs

    Thanks,

    Michael