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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [ARM7_STR71x_IAR/] [Library/] [wdg.c] - Rev 596
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/******************** (C) COPYRIGHT 2003 STMicroelectronics ******************** * File Name : WDG.c * Author : MCD Application Team * Date First Issued : 10/24/2003 * Description : This file provides all the WDG software functions ******************************************************************************** * History: * 30/11/2004 : V2.0 * 14/07/2004 : V1.3 * 01/01/2004 : V1.2 ******************************************************************************* THE PRESENT SOFTWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE CONTENT OF SUCH SOFTWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS. *******************************************************************************/ #include "wdg.h" #ifndef abs #define abs(x) ((x)>0 ? (x) : -(x)) #endif /******************************************************************************* * Function Name : FindFactors * Description : Search for the best (a,b) values that fit n = a*b * with the following constraints: 1<=a<=256, 1<=b<=65536 * Input 1 : n: the number to decompose * Input/Output 2 : a: a pointer to the first factor * Input/Output 3 : b: a pointer to the second factor * Return : None *******************************************************************************/ static void FindFactors(unsigned long n, unsigned int *a, unsigned long *b) { unsigned long b0; unsigned int a0; long err, err_min=n; *a = a0 = ((n-1)/65536ul) + 1; *b = b0 = n / *a; for (; *a <= 256; (*a)++) { *b = n / *a; err = (long)*a * (long)*b - (long)n; if (abs(err) > (*a / 2)) { (*b)++; err = (long)*a * (long)*b - (long)n; } if (abs(err) < abs(err_min)) { err_min = err; a0 = *a; b0 = *b; if (err == 0) break; } } *a = a0; *b = b0; } /******************************************************************************* * Function Name : WDG_PeriodValueConfig * Description : Set the prescaler and counter reload value * Input : Amount of time (us) needed * Return : None *******************************************************************************/ void WDG_PeriodValueConfig ( u32 Time ) { unsigned int a; unsigned long n, b; n = Time * (RCCU_FrequencyValue(RCCU_PCLK) / 1000000); FindFactors(n, &a, &b); WDG->PR = a - 1; WDG->VR = b - 1; } /******************* (C) COPYRIGHT 2003 STMicroelectronics *****END OF FILE****/
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