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STM32H7B3I-DK PLL3 VCO output exceeds 560MHz limit #275

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sirius506 opened this issue Sep 10, 2023 · 3 comments
Open

STM32H7B3I-DK PLL3 VCO output exceeds 560MHz limit #275

sirius506 opened this issue Sep 10, 2023 · 3 comments
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bsp BSP-related issue or pull-request. bug Something isn't working internal bug tracker Issue confirmed and reported into a ticket in the internal bug tracking system

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@sirius506
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STM32H7B3I-BK BSP LCD driver sets PLL3 VCO output to 800MHz.
I know it works, but Data sheet says maximum value is 560MHz.

/* RK043FN48H LCD clock configuration */
/* LCD clock configuration */
/* PLL3_VCO Input = HSE_VALUE/PLL3M = 4 Mhz */
/* PLL3_VCO Output = PLL3_VCO Input * PLL3N = 800 Mhz */
/* PLLLCDCLK = PLL3_VCO Output/PLL3R = 800/83 = 9.63 Mhz */
/* LTDC clock frequency = PLLLCDCLK = 9.63 Mhz */
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LTDC;
PeriphClkInitStruct.PLL3.PLL3M = 6;
PeriphClkInitStruct.PLL3.PLL3N = 200;
PeriphClkInitStruct.PLL3.PLL3P = 10;
PeriphClkInitStruct.PLL3.PLL3Q = 10;
PeriphClkInitStruct.PLL3.PLL3R = 83;
PeriphClkInitStruct.PLL3.PLL3VCOSEL = 0;
PeriphClkInitStruct.PLL3.PLL3FRACN = 0;

@ALABSTM ALABSTM added the bsp BSP-related issue or pull-request. label Sep 15, 2023
@ALABSTM ALABSTM added the bug Something isn't working label Oct 13, 2023
@TOUNSTM
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TOUNSTM commented Mar 7, 2024

Hello @sirius506,

Sorry for the delayed response. Could you please send me the document in which you find this information?

With regards,

@TOUNSTM TOUNSTM added the needs clarification Needs clarification from user label Mar 7, 2024
@TOUNSTM TOUNSTM moved this from To do to Analyzed in stm32cube-mcu-fw-dashboard Mar 7, 2024
@sirius506
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Please refer STM32H7B3I datasheet Table 55 on page 112. It says PLL VCO output max freq is 560MHz.

You can also try to set above listed PLL3 settings on the CubeMX clock config screen, then you'll see it responds with error indication (DIVN3 = 200 is too big).

@TOUNSTM
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TOUNSTM commented Mar 27, 2024

ST Internal Reference: 177140

@TOUNSTM TOUNSTM added internal bug tracker Issue confirmed and reported into a ticket in the internal bug tracking system and removed needs clarification Needs clarification from user labels Mar 27, 2024
@TOUNSTM TOUNSTM moved this from Analyzed to In progress in stm32cube-mcu-fw-dashboard Mar 27, 2024
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Labels
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