STM32F103 TIMCLK1 Issue

[paradislover]

Hi,

I just copy the clock setting from hal_lld_f103.h

Code: Select all

/**
 * @brief   AHB frequency.
 */
#if (STM32_HPRE == STM32_HPRE_DIV1) || defined(__DOXYGEN__)
#define STM32_HCLK                  (STM32_SYSCLK / 1)
#elif STM32_HPRE == STM32_HPRE_DIV2
#define STM32_HCLK                  (STM32_SYSCLK / 2)
#elif STM32_HPRE == STM32_HPRE_DIV4
#define STM32_HCLK                  (STM32_SYSCLK / 4)
#elif STM32_HPRE == STM32_HPRE_DIV8
#define STM32_HCLK                  (STM32_SYSCLK / 8)
#elif STM32_HPRE == STM32_HPRE_DIV16
#define STM32_HCLK                  (STM32_SYSCLK / 16)
#elif STM32_HPRE == STM32_HPRE_DIV64
#define STM32_HCLK                  (STM32_SYSCLK / 64)
#elif STM32_HPRE == STM32_HPRE_DIV128
#define STM32_HCLK                  (STM32_SYSCLK / 128)
#elif STM32_HPRE == STM32_HPRE_DIV256
#define STM32_HCLK                  (STM32_SYSCLK / 256)
#elif STM32_HPRE == STM32_HPRE_DIV512
#define STM32_HCLK                  (STM32_SYSCLK / 512)
#else
#error "invalid STM32_HPRE value specified"
#endif

/**
 * @brief   APB1 frequency.
 */
#if (STM32_PPRE1 == STM32_PPRE1_DIV1) || defined(__DOXYGEN__)
#define STM32_PCLK1                 (STM32_HCLK / 1)
#elif STM32_PPRE1 == STM32_PPRE1_DIV2
#define STM32_PCLK1                 (STM32_HCLK / 2)
#elif STM32_PPRE1 == STM32_PPRE1_DIV4
#define STM32_PCLK1                 (STM32_HCLK / 4)
#elif STM32_PPRE1 == STM32_PPRE1_DIV8
#define STM32_PCLK1                 (STM32_HCLK / 8)
#elif STM32_PPRE1 == STM32_PPRE1_DIV16
#define STM32_PCLK1                 (STM32_HCLK / 16)
#else
#error "invalid STM32_PPRE1 value specified"
#endif

#if (STM32_PPRE1 == STM32_PPRE1_DIV1) || defined(__DOXYGEN__)
#define STM32_TIMCLK1               (STM32_PCLK1 * 1)
#else
#define STM32_TIMCLK1               (STM32_PCLK1 * 2)
#endif

My setting is：

Code: Select all

/*
 * HAL driver system settings.
 */
#define STM32_NO_INIT                       FALSE
#define STM32_HSI_ENABLED                   TRUE
#define STM32_LSI_ENABLED                   FALSE
#define STM32_HSE_ENABLED                   TRUE
#define STM32_LSE_ENABLED                   FALSE
#define STM32_SW                            STM32_SW_PLL
#define STM32_PLLSRC                        STM32_PLLSRC_HSE
#define STM32_PLLXTPRE                      STM32_PLLXTPRE_DIV1
#define STM32_PLLMUL_VALUE                  9
#define STM32_HPRE                          STM32_HPRE_DIV1
#define STM32_PPRE1                         STM32_PPRE1_DIV2
#define STM32_PPRE2                         STM32_PPRE2_DIV1
#define STM32_ADCPRE                        STM32_ADCPRE_DIV6
#define STM32_USB_CLOCK_REQUIRED            TRUE
#define STM32_USBPRE                        STM32_USBPRE_DIV1P5
#define STM32_MCOSEL                        STM32_MCOSEL_NOCLOCK
#define STM32_RTCSEL                        STM32_RTCSEL_HSEDIV
#define STM32_PVD_ENABLE                    FALSE
#define STM32_PLS                           STM32_PLS_LEV0

then
STM32_TIMCLK1 = STM32_HCLK / 2 *2 = STM32_HCLK, but the STM32_TIMCLK1 should be half of AHB frequency.

If I have something miss understanding, please let me know.

[Giovanni]

Hi,

The explanation is in the Clock Tree image in the Reference Manual:

if (APB2 prescaler == 1) X1 else X2.

In your case the system clock is equal to the timers clock. It is divided by two then multiplied by two.

Giovanni

[paradislover]

Hi Giovanni ,

OK, got it. Thanks.