Machine cycle of MC9S12XHZ512 micro-controller.

kdn — Fri, 02 Jan 2015 04:37:25 GMT

How can I calculate machine cycle of MC9S12XHZ512 micro-controller.

I want to create time delay in MC9S12XHZ512 micro-controller using Timer, I have used 16MHz crystal on my micro-controller board with no prescale, Can someone explain me how can I calculate delay of 1ms if I am using 16-bit Timer.

Re: Machine cycle of MC9S12XHZ512 micro-controller.

lama — Tue, 06 Jan 2015 13:36:18 GMT

Here is an example for similar MCU with a lot of description:

/*******************************************************************************

* Freescale Semiconductor Inc.

********************************************************************************

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any warranty. CUSTOMER retains the final decision relative to the total design

and functionality of the end product. FREESCALE neither guarantees nor will be

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********************************************************************************

* File main.c

* Owner r62780

* Version 1.0

* Date Sep-15-2010

* Classification General Business Information

* Brief FLASH E/W

********************************************************************************

* Detailed Description:

* - the SW software demonstrates one of the possibilities how to generate SW

delay by means of ECT.

* - Generates only one impulse given length after the delay of given length

* - The hard delay, which means the CPU does not work on another task, is presented.

* It waits in loop.

* - Theory:

* interval = TCx * dt = TCx * (prescaler/fbus)

* TCx = interval / (prescaller/fbus) = interval * fbus / prescaler

* There are two ways for TCx and prescaler setup:

* 1) prescaler = constant (min and max interval is given)

* 2) prescaler and TCx are considered as a variables to calculate required interval

* interval = f(TCx, prescaler)

* this solution is more difficult

* This example solves item 1.

* - Prescaler = const = 8.

* - fbus = 8MHz

* - TCx = interval / (prescaller/fbus) = interval * fbus / prescaler

* Max interval can be calculated as interval[us]=65535*prescaler/fbus[MHz]

* and setup precision is dt=prescaler/fbus

* for fbus = 8MHz

* If prescaler = 1 then max interval is 8191.8 us; dt = 0.125 us

* If prescaler = 2 then max interval is 16383,7 us; dt = 0.250 us

* If prescaler = 4 then max interval is 32767,5 us; dt = 0.500 us

* If prescaler = 8 then max interval is 65535 us; dt = 1.000 us

* If prescaler = 16 then max interval is 131070 us; dt = 2.000 us

* If prescaler = 32 then max interval is 262140 us; dt = 4.000 us

* If prescaler = 64 then max interval is 524280 us; dt = 8.000 us

* If prescaler = 128 then max interval is 1048560 us; dt = 16.000 us

* - tested on: HCS12X STARTER KIT

* - OSCCLK = 16MHz, BUSCLK = 8MHz

* - Reference to documentation: MC9S12XDP512V2 Rev.2.17

********************************************************************************

Revision History:

Version Date Author Description of Changes

1.0 Sep-15-2010 R62780 Initial version

*******************************************************************************/

#include <hidef.h> // common defines and macros

#pragma LINK_INFO DERIVATIVE "mc9s12xdp512"

#include "map.h"

/*******************************************************************************

* Local function prototypes

*******************************************************************************/

static void Delay(UWORD interval);

static void ECT_Init(void);

/*******************************************************************************

* Local variables

*******************************************************************************/

// NONE

/*******************************************************************************

Function Name : ECT_Init

Engineer : r62780

Date : Sep/15/2010

Parameters : NONE

Modifies : NONE

Returns : NONE

Notes : Sets ECT for required functionality

Issues : NONE

*******************************************************************************/

static void ECT_Init(void)

{

TSCR2 = 0x03; // prescaller = 8

//--- channel 0 setup ---------------

TCTL1 = 0x00; // timer disconnected form output pin logic

TIOS = 0x01; // channels 0 is output compare

//-----------------------------------

TIE_C0I = 0; // disable interrupt from channel 0

//-----------------------------------

TSCR1 = 0xF0; // enable timer,stop in wait,stop in freeze, fast flag clear

}

/*******************************************************************************

Function Name : Delay

Engineer : r62780

Date : Sep/15/2010

Parameters : UWORD interval

Modifies : NONE

Returns : NONE

Notes : Performs hard delay

Issues : NONE

*******************************************************************************/

static void Delay(UWORD interval)

{

TC0 = TCNT + interval; // set new value and clear interrupt flag

// TC0 = t + interval * fbus / prescaler;

while(!TFLG1_C0F);

}

/*******************************************************************************

Function Name : main

Engineer : r62780

Date : Sep/15/2010

Parameters : NONE

Modifies : NONE

Returns : NONE

Notes : Demonstrate SW delay

Issues : NONE

*******************************************************************************/

void main(void)

{

for(;;)

{

//----------------------------------

ECT_Init();

//----------------------------------

DDRB=0xFF; // an output port to visualize period

//----------------------------------

for(;;)

{

Delay(10000); // true delay is value 500*prescaller/busclk=

// = 10000*8/8MHz = 10000us = 10ms

PORTB = ~PORTB;

}

/*******************************************************************************

The Answer to the Ultimate Question of Life, the Universe, and Everything is:.......... 42.

(Douglas Adams - The Hitchhiker's Guide to the Galaxy)

*******************************************************************************/

topic Re: Machine cycle of MC9S12XHZ512 micro-controller. in S12 / MagniV Microcontrollers

Machine cycle of MC9S12XHZ512 micro-controller.

Re: Machine cycle of MC9S12XHZ512 micro-controller.