arch/arm/src/stm32h7/stm32_timerisr.c: Update comments to refernce the errata related to the SysTick clock not being HCLK/8.

This commit is contained in:
Gregory Nutt 2019-03-06 12:45:48 -06:00
parent 76781e16e0
commit c21be8856c

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@ -66,6 +66,18 @@
* The SysTick calibration value is fixed to 18750, which gives a reference
* time base of 1 ms with the SysTick clock set to 18.75 MHz (HCLK/8, with
* HCLK set to 150 MHz).
*
* REVISIT: Per ES0392 Rev 4: STM32H743xI Errata sheet STM32H743xI device
* limitations
*
* SysTick external clock is not HCLK/8
* Description
* The SysTick external clock is the system clock, instead of the system
* clock divided by 8 (HCLK/8).
* Workaround
* Use the system clock (HCLK) as external clock and multiply the reload
* value by 8 in STK_LOAD register (take care that the maximum value is
* 224-1).
*/
#undef CONFIG_STM32H7_SYSTICK_HCLKd8