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Mrinmoy
Joined: 20 Dec 2023
Posts: 16
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| PIC24F Clock frequency multiply problem |
 Posted: Fri Sep 20, 2024 1:40 am |
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Hi Everyone,
I am using PIC24FJ512GL406 mcu in one of my project and using 32MHz external oscillator and want to double the clock frequency by using PLL.
| Code: |
//********* CPU Settings *******************************************
#device ICSP = 1
#pragma use delay(osc=32000000,clock=64000000,restart_wdt,clock_out)
#pragma fuses NOPROTECT,WDT,NOBROWNOUT,DEBUG,CKSNOFSM
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This is my system setup code but not working.
If I change my line like -
| Code: |
#pragma use delay(clock=64MHz,osc,restart_wdt,clock_out)
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Then the code will run but timer is not matching with 64MHz calculation and also clock out PIN shows 16MHz.
Any help will be highly appreciated.
Thanks in advance  [/code] |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19966
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| Posted: Fri Sep 20, 2024 3:59 am |
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The 16MHz, is right. Data sheet. CLKO = FOSC/2.
Are you sure what frequency you are running the timer off?. The timers by
default are run off the 'peripheral clock'. This is also FOSC/2. Look at
figure 9-1. |
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gaugeguy
Joined: 05 Apr 2011
Posts: 350
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| Posted: Fri Sep 20, 2024 5:53 am |
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With that processor, the CPU can only run at up to 32MHz. The PLL can be used to get 48MHz for the USB.
You cannot run the processor at 64MHz. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19966
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| Posted: Sat Sep 21, 2024 12:21 am |
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| Spot on. Maximum CPU instruction speed is 16MHz. Max clock 32MHz. |
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Mrinmoy
Joined: 20 Dec 2023
Posts: 16
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| Posted: Sat Sep 21, 2024 1:19 am |
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Yes! I just check it.
CPU of that particular controller can run maximum at 16MHz.
Thanks guys. |
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