tc.c File Reference

#include "board.h"
#include <assert.h>

Functions
void	TC_Configure (Tc *pTc, uint32_t dwChannel, uint32_t dwMode)
	Configures a Timer Counter Channel.
void	TC_Start (Tc *pTc, uint32_t dwChannel)
	Reset and Start the TC Channel.
void	TC_Stop (Tc *pTc, uint32_t dwChannel)
	Stop TC Channel.
uint32_t	TC_FindMckDivisor (uint32_t dwFreq, uint32_t dwMCk, uint32_t *dwDiv, uint32_t *dwTcClks, uint32_t dwBoardMCK)
	Find best MCK divisor.

Detailed Description

Purpose

Interface for configuring and using Timer Counter (TC) peripherals.

Usage

1. Optionally, use TC_FindMckDivisor() to let the program find the best TCCLKS field value automatically.
2. Configure a Timer Counter in the desired mode using TC_Configure().
3. Start or stop the timer clock using TC_Start() and TC_Stop().

Implementation of Timer Counter (TC).

Function Documentation

TC_Configure()

void TC_Configure	(	Tc *	pTc,
		uint32_t	dwChannel,
		uint32_t	dwMode
	)

Configures a Timer Counter Channel.

Configures a Timer Counter to operate in the given mode. Timer is stopped after configuration and must be restarted with TC_Start(). All the interrupts of the timer are also disabled.

Parameters

pTc	Pointer to a Tc instance.
channel	Channel number.
mode	Operating mode (TC_CMR value).

TC_FindMckDivisor()

uint32_t TC_FindMckDivisor	(	uint32_t	dwFreq,
		uint32_t	dwMCk,
		uint32_t *	dwDiv,
		uint32_t *	dwTcClks,
		uint32_t	dwBoardMCK
	)

Find best MCK divisor.

Finds the best MCK divisor given the timer frequency and MCK. The result is guaranteed to satisfy the following equation:

(MCK / (DIV * 65536)) <= freq <= (MCK / DIV)

with DIV being the highest possible value.

Parameters

dwFreq	Desired timer frequency.
dwMCk	Master clock frequency.
dwDiv	Divisor value.
dwTcClks	TCCLKS field value for divisor.
dwBoardMCK	Board clock frequency.

Returns

1 if a proper divisor has been found, otherwise 0.

TC_Start()

void TC_Start	(	Tc *	pTc,
		uint32_t	dwChannel
	)

Reset and Start the TC Channel.

Enables the timer clock and performs a software reset to start the counting.

Parameters

pTc	Pointer to a Tc instance.
dwChannel	Channel number.

TC_Stop()

void TC_Stop	(	Tc *	pTc,
		uint32_t	dwChannel
	)

Stop TC Channel.

Disables the timer clock, stopping the counting.

Parameters

pTc	Pointer to a Tc instance.
dwChannel	Channel number.