Subversion Repositories neo430

// #################################################################################################
// #  < neo430_pwm.c - PWM controller helper functions >                                           #
// # ********************************************************************************************* #
// # BSD 3-Clause License                                                                          #
// #                                                                                               #
// # Copyright (c) 2020, Stephan Nolting. All rights reserved.                                     #
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// #    permission.                                                                                #
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// # ********************************************************************************************* #
// # The NEO430 Processor - https://github.com/stnolting/neo430                                    #
// #################################################################################################
 
#include "neo430.h"
#include "neo430_pwm.h"
 
 
/* ------------------------------------------------------------
 * INFO Reset and activate PWM controller
 * PARAM prsc: Clock prescaler for PWM clock
 * PARAM size: 1=use 8-bit counter, 0=use 4-bit counter
 * PARAM gpio_pwm: Use channel 3 for GPIO.output modulation when 1
 * ------------------------------------------------------------ */
void neo430_pwm_enable(const uint16_t prsc, const uint16_t size, const uint16_t gpio_pwm) {
 
  PWM_CT = 0; // reset
  PWM_CT = (1<<PWM_CT_EN) | (prsc<<PWM_CT_PRSC0) | (size<<PWM_CT_SIZE_SEL) | (gpio_pwm<<PWM_CT_GPIO_PWM);
}
 
 
/* ------------------------------------------------------------
 * INFO Disable PWM controller
 * ------------------------------------------------------------ */
void neo430_pwm_disable(void) {
 
  PWM_CT = 0;
}
 
 
/* ------------------------------------------------------------
 * INFO Set duty cycle of channel
 * PARAM channel 0..3
 * PARAM 8-bit duty cycle
 * ------------------------------------------------------------ */
void neo430_pwm_set(uint8_t channel, uint8_t dc) {
 
  uint16_t duty_cycle = 0;
 
  // get current state
  if (channel & 2) // channel 2 or 3
    duty_cycle = PWM_CH32;
  else // channel 1 or 0
    duty_cycle = PWM_CH10;
 
  // modify high or low part (even or odd channel)
  if (channel & 1) { // channel 1 or 3
    duty_cycle &= 0x00ff;
    duty_cycle |= ((uint16_t)dc) << 8;
  }
  else { // channel 0 or 2
    duty_cycle &= 0xff00;
    duty_cycle |= ((uint16_t)dc) << 0;
  }
 
  // write back
  if (channel & 2) // channel 2 or 3
    PWM_CH32 = duty_cycle;
  else // channel 1 or 0
    PWM_CH10 = duty_cycle;
}