topic Re: Implmenting Tick Timer in KE1xZ in Kinetis Microcontrollers

Implmenting Tick Timer in KE1xZ

Jmir — Fri, 12 Mar 2021 11:30:07 GMT

I will need to implement a 10ms tick timer for a real time control system in KE1xZ.

Should it be implemented in the FTM module or in the LPIT?

Re: Implmenting Tick Timer in KE1xZ

mjbcswitzerland — Fri, 12 Mar 2021 15:08:25 GMT

Typically the SYSTICK is used for tick in all Kinetis (Cortex) parts.

Regards

Mark
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Re: Implmenting Tick Timer in KE1xZ

gusarambula — Fri, 12 Mar 2021 18:05:21 GMT

Hello Jmir,

Both timers may generate the required signal, albeit they have different features depending on your application:

The FTM (Flex Timer Module) is very flexible, as the name suggest, as it has additional modes like input capture or output compare, for example.

The LPIT (Low-power Periodic Interrupt Timer) can operate in low power modes so it’s mostly used for operations required in low power mode.

In regards as a tick timer for a real time control system, as Mark mentioned, in Kinetis microcontrollers usually use the SysTick timer is used instead, which is part of the Cortex-M0+ features.

Regards,
Gustavo

Re: Implmenting Tick Timer in KE1xZ

Jmir — Wed, 31 Mar 2021 15:09:29 GMT

I have been looking in the KE1xZ reference manual for information on SysTick, however I cannot find which registers I have to configure to program a 10ms tick capable of generating an interruption.

Can you help me?

Re: Implmenting Tick Timer in KE1xZ

ErichStyger — Wed, 31 Mar 2021 16:17:56 GMT

The SysTick is part of the ARM Core and the ARM manuals. You can easily use the SDK and CMSIS headers to configure it, e.g. with the following example:

/* * Copyright (c) 2021, Erich Styger * * SPDX-License-Identifier: BSD-3-Clause */ #include "systick.h" #include "fsl_common.h" static volatile uint32_t g_systickCounter; void SysTick_Handler(void) { if (g_systickCounter != 0U) { g_systickCounter--; } } void SysTick_DelayTicks(uint32_t n) { g_systickCounter = n; while (g_systickCounter != 0U) { } } void SysTick_Init(void) { g_systickCounter = 0; SysTick_Config(MSEC_TO_COUNT(1, SystemCoreClock)); /* 1 ms tick period */ }

I hope this helps,

Erich