/******************************************************************************
* [url=home.php?mod=space&uid=288409]@file[/url] main.c
* [url=home.php?mod=space&uid=895143]@version[/url] V1.00
* $Revision: 3 $
* $Date: 13/10/07 3:54p $
* [url=home.php?mod=space&uid=247401]@brief[/url] PWM sample for Mini51 series MCU
*
* @note
* Copyright (C) 2013 Nuvoton Technology Corp. All rights reserved.
*****************************************************************************/
#include <stdio.h>
#include "Mini51Series.h"
void SYS_Init(void)
{
/*---------------------------------------------------------------------------------------------------------*/
/* Init System Clock */
/*---------------------------------------------------------------------------------------------------------*/
/* Unlock protected registers */
while(SYS->RegLockAddr != 1) {
SYS->RegLockAddr = 0x59;
SYS->RegLockAddr = 0x16;
SYS->RegLockAddr = 0x88;
}
/* Enable external 12MHz XTAL, internal 22.1184MHz */
CLK->PWRCON = CLK_PWRCON_IRC22M_EN_Msk;
/* Waiting for clock ready */
while(!(CLK->CLKSTATUS & CLK_CLKSTATUS_IRC22M_STB_Msk));
/* Enable IP clock */
CLK->APBCLK = CLK_APBCLK_UART_EN_Msk | CLK_APBCLK_PWM23_EN_Msk;
/* Update System Core Clock */
/* User can use SystemCoreClockUpdate() to calculate SystemCoreClock and CycylesPerUs automatically. */
SystemCoreClockUpdate();
/*---------------------------------------------------------------------------------------------------------*/
/* Init I/O Multi-function */
/*---------------------------------------------------------------------------------------------------------*/
/* Set P1 multi-function pins for UART RXD, TXD */
SYS->P0_MFP = SYS_MFP_P00_TXD | SYS_MFP_P01_RXD;
/* Set P2 multi-function pins for PWM Channel */
SYS->P2_MFP = SYS_MFP_P24_PWM2;
/* Lock protected registers */
SYS->RegLockAddr = 0;
}
void UART_Init(void)
{
// Set UART to 8 bit character length, 1 stop bit, and no parity
UART->LCR = UART_LCR_WLS_Msk;
// 22.1184 MHz reference clock input, for 115200 bps
// 22118400 / 115200 = 192. Using mode 2 to calculate baudrate, 192 - 2 = 190 = 0xBE
UART->BAUD = UART_BAUD_DIV_X_EN_Msk | UART_BAUD_DIV_X_ONE_Msk | (0xBE);
}
int32_t main (void)
{
/* Init System, IP clock and multi-function I/O
In the end of SYS_Init() will issue SYS_LockReg()
to lock protected register. If user want to write
protected register, please issue SYS_UnlockReg()
to unlock protected register if necessary */
SYS_Init();
/* Init UART to 115200-8n1 for print message */
UART_Init();
printf("\nThis sample code will output PWM channel 0 to output waveform\n");
printf("using double buffer feature.\n");
/*
PWM channel 0 wave form of this sample showns below:
|<- CNR + 1 clk ->| CNR + 1 = 199 + 1 CLKs
|<-CMR+1 clk ->| CMR + 1 = 99 + 1 CLKs
|<- CNR + 1 ->| CNR + 1 = 99 + 1 CLKs
|<CMR+1>| CMR + 1 = 39 + 1 CLKs
______________ ________ _____
__| 100 |_____100______| 60 |__40___| PWM waveform
*/
// Set channel 0 perscaler to 2. Actual value fill into register needs to minus 1.
PWM->PPR = 0x0100;
// Set channel 0 clock divider to 1
PWM->CSR = PWM_CLK_DIV_1 << PWM_CSR_CSR2_Pos;
// Enable PWM channel 0 auto-reload mode
PWM->PCR = PWM_PCR_CH2MOD_Msk;
/*
Configure PWM channel 1 init period and duty.
Period is HCLK / (perscaler * clock divider * (CNR + 1))
Duty ratio = (CMR + 1) / (CNR + 1)
Period = 22.1184 MHz / (1 * 1 * (1B9 + 1)) = 25000 Hz
Duty ratio = (99 + 1) / (199 + 1) = 50%
*/
PWM->CMR[2] = 0xB9;
PWM->CNR[2] = 0x1B9;
// Enable PWM channel 2 output
PWM->POE = PWM_POE_PWM2_Msk;
// Start
PWM->PCR |= PWM_PCR_CH2EN_Msk;
while(1);
}
/*** (C) COPYRIGHT 2013 Nuvoton Technology Corp. ***/
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