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DRA821U: Changing System clock to 25MHz

Hi TI
In order to catch packet loss of SGMII (1000BASET1), the system clock was changed from 19.2Mhz to 25Mhz.
Nothing unusual so far, but it seems like there should be a change in U-boot when crystal changes in the link below
If you need to change it to 25 MHz, please guide us.
Thanks.
Regards, 
Jack
  • Hello Jack,

    Can you please provide the link you mentioned, it seems to be missing.

    Regards,

    Erick

  • Eric.

    Sorry I missed the link mentioned above.

    https://e2e.ti.com/support/processors-group/processors/f/processors-forum/993992/am3359-uart2-output-baudrate-is-more-than-configured-value/3695020?tisearch=e2e-sitesearch&keymatch=uart%252525252520baudrate%25252525252019200#3695020

    Here is the clock info for their system. 

    root@tgu:/sys/class/gpio/gpio485#  cat /sys/kernel/debug/clk/clk_summary
                                     enable  prepare  protect                                duty
       clock                          count    count    count        rate   accuracy phase  cycle
    ---------------------------------------------------------------------------------------------
    clk:292:89                           0        0        0   100000000          0     0  50000
        clk:292:85                        0        0        0   100000000          0     0  50000
           bus@100000:wiz@5060000_refclk-dig       0        0        0   100000000          0     0  50000
           bus@100000:wiz@5060000_pll1-refclk       0        0        0   100000000          0     0  50000
           bus@100000:wiz@5060000_pll0-refclk       0        0        0   100000000          0     0  50000
    clk:292:88                           0        0        0   125000000          0     0  50000
    clk:292:87                           0        0        0           0          0     0  50000
    clk:292:86                           0        0        0    25000000          0     0  50000
    clk:292:11                           0        0        0   125000000          0     0  50000
    clk:288:14                           0        0        0           0          0     0  50000
    clk:288:13                           0        0        0    25000000          0     0  50000
        clk:288:12                        0        0        0    25000000          0     0  50000
    clk:288:3                            0        0        0    24000000          0     0  50000
    clk:287:4                            0        0        0    25000000          0     0  50000
    clk:287:3                            0        0        0    96000000          0     0  50000
        clk:287:2                         0        0        0    96000000          0     0  50000
    clk:286:2                            0        0        0    48000000          0     0  50000
    clk:283:2                            0        0        0    48000000          0     0  50000
    clk:282:2                            0        0        0    48000000          0     0  50000
    clk:280:2                            0        0        0    48000000          0     0  50000
    clk:279:2                            0        0        0    48000000          0     0  50000
    clk:278:2                            0        0        0    48000000          0     0  50000
    clk:266:4                            0        0        0    50000000          0     0  50000
    clk:253:9                            0        0        0           0          0     0  50000
    clk:253:8                            0        0        0           0          0     0  50000
    clk:253:7                            0        0        0           0          0     0  50000
    clk:253:6                            0        0        0           0          0     0  50000
    clk:253:5                            0        0        0       32550          0     0  50000
        clk:253:1                         0        0        0       32550          0     0  50000
    clk:253:4                            0        0        0    12500000          0     0  50000
    clk:253:3                            0        0        0           0          0     0  50000
    clk:253:2                            0        0        0    25000000          0     0  50000
    clk:252:9                            0        0        0           0          0     0  50000
    clk:252:8                            0        0        0           0          0     0  50000
    clk:252:7                            0        0        0           0          0     0  50000
    clk:252:6                            0        0        0           0          0     0  50000
    clk:252:5                            0        0        0       32550          0     0  50000
        clk:252:1                         0        0        0       32550          0     0  50000
    clk:252:4                            0        0        0    12500000          0     0  50000
    clk:252:3                            0        0        0           0          0     0  50000
    clk:252:2                            0        0        0    25000000          0     0  50000
    clk:201:17                           0        0        0   500000000          0     0  50000
    clk:201:16                           0        0        0   500000000          0     0  50000
    clk:201:15                           0        0        0           0          0     0  50000
    clk:201:14                           0        0        0           0          0     0  50000
    clk:201:13                           0        0        0           0          0     0  50000
    clk:201:12                           0        0        0           0          0     0  50000
    clk:201:11                           0        0        0           0          0     0  50000
    clk:201:10                           0        0        0           0          0     0  50000
    clk:201:9                            0        0        0           0          0     0  50000
    clk:201:8                            0        0        0           0          0     0  50000
    clk:201:7                            0        0        0           0          0     0  50000
    clk:201:6                            0        0        0           0          0     0  50000
    clk:201:5                            0        0        0           0          0     0  50000
    clk:201:4                            0        0        0           0          0     0  50000
    clk:201:3                            0        0        0   200000000          0     0  50000
    clk:201:2                            0        0        0   200000000          0     0  50000
        clk:201:1                         0        0        0   200000000          0     0  50000
    clk:197:1                            0        0        0    96000000          0     0  50000
    clk:195:1                            0        0        0    96000000          0     0  50000
    clk:194:1                            0        0        0    96000000          0     0  50000
    clk:193:1                            0        0        0    96000000          0     0  50000
    clk:192:1                            0        0        0    96000000          0     0  50000
    clk:191:1                            0        0        0    96000000          0     0  50000
    clk:190:1                            0        0        0    96000000          0     0  50000
    clk:189:1                            0        0        0    96000000          0     0  50000
    clk:188:1                            0        0        0    96000000          0     0  50000
    clk:187:1                            0        0        0    96000000          0     0  50000
    clk:171:6                            0        0        0    25000000          0     0  50000
    clk:171:5                            0        0        0           0          0     0  50000
    clk:171:4                            0        0        0           0          0     0  50000
    clk:171:3                            0        0        0    80000000          0     0  50000
        clk:171:2                         0        0        0    80000000          0     0  50000
    clk:171:0                            0        0        0   125000000          0     0  50000
    clk:170:6                            0        0        0    25000000          0     0  50000
    clk:170:5                            0        0        0           0          0     0  50000
    clk:170:4                            0        0        0           0          0     0  50000
    clk:170:3                            0        0        0    80000000          0     0  50000
        clk:170:2                         0        0        0    80000000          0     0  50000
    clk:170:0                            0        0        0   125000000          0     0  50000
    clk:168:6                            0        0        0    25000000          0     0  50000
    clk:168:5                            0        0        0           0          0     0  50000
    clk:168:4                            0        0        0           0          0     0  50000
    clk:168:3                            0        0        0    80000000          0     0  50000
        clk:168:2                         0        0        0    80000000          0     0  50000
    clk:168:0                            0        0        0   125000000          0     0  50000
    clk:162:6                            0        0        0    25000000          0     0  50000
    clk:162:5                            0        0        0           0          0     0  50000
    clk:162:4                            0        0        0           0          0     0  50000
    clk:162:3                            0        0        0    80000000          0     0  50000
        clk:162:2                         0        0        0    80000000          0     0  50000
    clk:162:0                            0        0        0   125000000          0     0  50000
    clk:156:6                            0        0        0    25000000          0     0  50000
    clk:156:5                            0        0        0           0          0     0  50000
    clk:156:4                            0        0        0           0          0     0  50000
    clk:156:3                            0        0        0    80000000          0     0  50000
        clk:156:2                         0        0        0    80000000          0     0  50000
    clk:156:0                            0        0        0   125000000          0     0  50000
    clk:151:6                            0        0        0    25000000          0     0  50000
    clk:151:5                            0        0        0           0          0     0  50000
    clk:151:4                            0        0        0           0          0     0  50000
    clk:151:3                            0        0        0    80000000          0     0  50000
        clk:151:2                         0        0        0    80000000          0     0  50000
    clk:151:0                            0        0        0   125000000          0     0  50000
    clk:149:4                            0        0        0   192000000          0     0  50000
    clk:149:3                            0        0        0    96000000          0     0  50000
        clk:149:2                         0        0        0    96000000          0     0  50000
    clk:146:2                            0        0        0    48000000          0     0  50000
    clk:113:4                            0        0        0    12500000          0     0  50000
    clk:113:3                            0        0        0       32550          0     0  50000
    clk:113:2                            0        0        0   166666666          0     0  50000
    clk:113:1                            1        1        0   166666666          0     0  50000
        clk:113:0                         1        1        0   166666666          0     0  50000
    clk:105:0                            1        1        0   125000000          0     0  50000
    clk:102:5                            0        0        0   166666666          0     0  50000
    clk:102:0                            0        0        0           0          0     0  50000
    clk:92:6                             0        0        0   200000000          0     0  50000
    clk:92:5                             0        0        0   200000000          0     0  50000
    clk:92:4                             0        0        0   192000000          0     0  50000
    clk:92:3                             1        1        0   200000000          0     0  50000
        clk:92:2                          1        1        0   200000000          0     0  50000
    clk:92:1                             0        0        0   250000000          0     0  50000
    clk:91:7                             0        0        0   200000000          0     0  50000
    clk:91:6                             0        0        0   200000000          0     0  50000
    clk:91:5                             0        0        0   192000000          0     0  50000
    clk:91:4                             1        1        0   200000000          0     0  50000
        clk:91:3                          1        1        0   200000000          0     0  50000
    clk:91:0                             0        0        0   250000000          0     0  50000
    clk:19:33                            0        0        0   320000000          0     0  50000
    clk:19:16                            0        0        0   200000000          0     0  50000
    clk:18:21                            0        0        0   333333333          0     0  50000
    clk:18:18                            0        0        0   500000000          0     0  50000
        clk:18:2                          0        0        0   500000000          0     0  50000
    clk:18:17                            0        0        0   500000000          0     0  50000
    clk:18:16                            0        0        0           0          0     0  50000
    clk:18:15                            0        0        0           0          0     0  50000
    clk:18:14                            0        0        0           0          0     0  50000
    clk:18:13                            0        0        0           0          0     0  50000
    clk:18:12                            0        0        0           0          0     0  50000
    clk:18:11                            0        0        0           0          0     0  50000
    clk:18:10                            0        0        0           0          0     0  50000
    clk:18:9                             0        0        0           0          0     0  50000
    clk:18:8                             0        0        0           0          0     0  50000
    clk:18:7                             0        0        0           0          0     0  50000
    clk:18:6                             0        0        0           0          0     0  50000
    clk:18:5                             0        0        0           0          0     0  50000
    clk:18:4                             0        0        0   200000000          0     0  50000
    clk:18:3                             0        0        0   200000000          0     0  50000
    clk:0:5                              0        0        0           0          0     0  50000
    clk:0:4                              0        0        0    58823529          0     0  50000
    clk:0:3                              0        0        0    60000000          0     0  50000
    clk:0:2                              0        0        0    25000000          0     0  50000
        clk:0:1                           0        0        0    25000000          0     0  50000
    serdes-refclk                        0        0        0   100000000          0     0  50000
    bus@100000:wiz@5060000_cmn-refclk-dig-div       0        0        0           0          0     0  50000
    
    

    Thanks.

    Regards, 

    Jack

  • Jack,

    Typically the DIP switch settings take care of the system clock configuration:

    Are you seeing issues with clock frequencies?

    - Keerthy

  • Hi Keerthy J,

      As mentioned above, we use 25MHz system clock instead of 19.2MHz to solve the packet loss problem at CPSW5G.

      Actually, we have two problems in now. One is USB3.0 is not work correctly with SGMII interface. Other is baud rate of one of UART is not work correctly. So we thought that the change of system clock can be the reason of problem.

      As your mention, we just changed DIP switch (bootstrap) and we didn't change any software. Just we want to check again that does it required any change of software part. If you can confirm, we can close this issue.

      In fact, UART problem seems related with wkup_uart0 problem.

    https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1225928/dra821u-changing-uart0-3-baudrate/4633442#4633442

    - YoungHan Kim

  • As your mention, we just changed DIP switch (bootstrap) and we didn't change any software. Just we want to check again that does it required any change of software part. If you can confirm, we can close this issue.

    I check internally and NOcode change should be necessary.

    Thanks,
    Keerthy

  • Hi Keerthy J,

    Thanks for your confifmation.

    Please close this issue.

    Thanks

    YoungHan Kim