topic Re: SysTick_Config in LPCXpresso IDE

SysTick_Config

lpcware — Thu, 16 Jun 2016 02:49:32 GMT

Content originally posted in LPCWare by jlara on Wed Feb 02 19:29:10 MST 2011
Which of the following is correct? I have seen it done both ways in the examples.

SysTick_Config(SystemCoreClock/1000)
or
SysTick_Config(SystemCoreClock/1000 - 1)

Thanks in advance.

Re: SysTick_Config

lpcware — Thu, 16 Jun 2016 02:49:33 GMT

Content originally posted in LPCWare by Albert on Wed Feb 02 21:24:10 MST 2011
Hi jlara,

Period = (RELOAD+1)/Clock -> RELOAD = Period*Clock-1.

If Period =10ms and clock = 100MHz
RELOAD = 10ms*100MHz - 1 = 999999.

But, the parameter on CMSIS funcion is RELOAD + 1

SysTick_Config(RELOAD + 1)

Then, for Period =10ms and clock = 100MHz we have:

SysTick_Config(999999+ 1) = SysTick_Config(1000000) = SysTick_Config(SystemCoreClock/1000)

Re: SysTick_Config

R3t0 — Wed, 14 Jul 2021 12:54:49 GMT

Thanks for the explanation of the SysTick_Config() function. In the Clock Config Tools, the Systick Clock can also be set, what is the connection to the SysTick_Config() function here?

Re: SysTick_Config

SpoonMan — Tue, 14 Feb 2023 15:44:05 GMT

Final result is wrong... 1e8 / 1e3 == 1e5 != 10e-3 * 100e6 == 1e8 / 1e2
Looks embarassing...