tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Maxim/TARGET_MAX32610/pwmout_api.c

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  33
  34 #include "mbed_assert.h"
  35 #include "cmsis.h"
  36 #include "pwmout_api.h"
  37 #include "pinmap.h"
  38 #include "ioman_regs.h"
  39 #include "clkman_regs.h"
  40 #include "PeripheralPins.h"
  41
  42 //******************************************************************************
  43 void pwmout_init(pwmout_t* obj, PinName pin)
  44 {
  45     // Make sure the pin is free for GPIO use
  46     unsigned int port = (unsigned int)pin >> PORT_SHIFT;
  47     unsigned int port_pin = (unsigned int)pin & ~(0xFFFFFFFF << PORT_SHIFT);
  48     MBED_ASSERT(MXC_GPIO->free[port] & (0x1 << port_pin));
  49
  50     int i = 0;
  51     PinMap pwm = PinMap_PWM[0];
  52
  53     // Check if there is a pulse train already active on this port
  54     int pin_func = (MXC_GPIO->func_sel[port] & (0xF << (port_pin*4))) >> (port_pin*4);
  55     if((pin_func > 0) && (pin_func < 4)) {
  56         // Search through PinMap_PWM to find the active PT
  57         while(pwm.pin != (PinName)NC) {
  58             if((pwm.pin == pin) && (pwm.function == pin_func)) {
  59                 break;
  60             }
  61             pwm = PinMap_PWM[++i];
  62         }
  63
  64     } else {
  65        // Search through PinMap_PWM to find an available PT
  66         int i = 0;
  67         while(pwm.pin != (PinName)NC && (i > -1)) {
  68             pwm = PinMap_PWM[i++];
  69             if(pwm.pin == pin) {
  70                 // Check each instance of PT
  71                 while(1) {
  72                     // Check to see if this PT instance is already in use
  73                     if((((mxc_pt_regs_t*)pwm.peripheral)->rate_length &
  74                         MXC_F_PT_RATE_LENGTH_MODE)) {
  75                         i = -1;
  76                         break;
  77                     }
  78
  79                     // If all instances are in use, overwrite the last
  80                     pwm = PinMap_PWM[++i];
  81                     if(pwm.pin != pin) {
  82                         pwm = PinMap_PWM[--i];
  83                         i = -1;
  84                         break;
  85                     }
  86
  87                 }
  88             }
  89         }
  90     }
  91
  92     // Make sure we found an available PWM generator
  93     MBED_ASSERT(pwm.pin != (PinName)NC);
  94
  95     // Disable all pwm output
  96     MXC_PTG->ctrl = 0;
  97
  98     // Enable the clock
  99     MXC_CLKMAN->clk_ctrl_2_pt = MXC_E_CLKMAN_CLK_SCALE_ENABLED;
 100
 101     // Set the drive mode to normal
 102     MXC_SET_FIELD(&MXC_GPIO->out_mode[port], (0x7 << (port_pin*4)), (MXC_V_GPIO_OUT_MODE_NORMAL_DRIVE << (port_pin*4)));
 103
 104     // Set the obj pointer to the propper PWM instance
 105     obj->pwm = (mxc_pt_regs_t*)pwm.peripheral;
 106
 107     // Initialize object period and pulse width
 108     obj->period = -1;
 109     obj->pulse_width = -1;
 110
 111     // Disable the output
 112     obj->pwm->train = 0x0;
 113     obj->pwm->rate_length = 0x0;
 114
 115     // Configure the pin
 116     pin_mode(pin, (PinMode)PullNone);
 117     pin_function(pin, pwm.function);
 118
 119     // default to 20ms: standard for servos, and fine for e.g. brightness control
 120     pwmout_period_us(obj, 20000);
 121     pwmout_write    (obj, 0);
 122
 123     // Enable the global pwm
 124     MXC_PTG->ctrl = MXC_F_PT_CTRL_ENABLE_ALL;
 125 }
 126
 127 //******************************************************************************
 128 void pwmout_free(pwmout_t* obj)
 129 {
 130     // Set the registers to the reset value
 131     obj->pwm->train = 0;
 132     obj->pwm->rate_length = 0x08000000;
 133 }
 134
 135 //******************************************************************************
 136 static void pwmout_update(pwmout_t* obj)
 137 {
 138     // Calculate and set the divider ratio
 139     int div = (obj->period * (SystemCoreClock/1000000))/32;
 140     if (div < 2){
 141         div = 2;
 142     }
 143     MXC_SET_FIELD(&obj->pwm->rate_length, MXC_F_PT_RATE_LENGTH_RATE_CONTROL, div);
 144
 145     // Change the duty cycle to adjust the pulse width
 146     obj->pwm->train = (0xFFFFFFFF << (32-((32*obj->pulse_width)/obj->period)));
 147 }
 148
 149
 150 //******************************************************************************
 151 void pwmout_write(pwmout_t* obj, float percent)
 152 {
 153     // Saturate percent if outside of range
 154     if(percent < 0.0) {
 155         percent = 0.0;
 156     } else if(percent > 1.0) {
 157         percent = 1.0;
 158     }
 159
 160     // Resize the pulse width to set the duty cycle
 161     pwmout_pulsewidth_us(obj, (int)(percent*obj->period));
 162 }
 163
 164 //******************************************************************************
 165 float pwmout_read(pwmout_t* obj)
 166 {
 167     // Check for when pulsewidth or period equals 0
 168     if((obj->pulse_width == 0) || (obj->period == 0)){
 169         return 0;
 170     }
 171
 172     // Return the duty cycle
 173     return ((float)obj->pulse_width / (float)obj->period);
 174 }
 175
 176 //******************************************************************************
 177 void pwmout_period(pwmout_t* obj, float seconds)
 178 {
 179     pwmout_period_us(obj, (int)(seconds * 1000000.0));
 180 }
 181
 182 //******************************************************************************
 183 void pwmout_period_ms(pwmout_t* obj, int ms)
 184 {
 185     pwmout_period_us(obj, ms*1000);
 186 }
 187
 188 //******************************************************************************
 189 void pwmout_period_us(pwmout_t* obj, int us)
 190 {
 191     // Check the range of the period
 192     MBED_ASSERT((us >= 0) && (us <= (int)(SystemCoreClock/32)));
 193
 194     // Set pulse width to half the period if uninitialized
 195     if(obj->pulse_width == -1){
 196         obj->pulse_width = us/2;
 197     }
 198
 199     // Save the period
 200     obj->period = us;
 201
 202     // Update the registers
 203     pwmout_update(obj);
 204 }
 205
 206 //******************************************************************************
 207 void pwmout_pulsewidth(pwmout_t* obj, float seconds)
 208 {
 209     pwmout_pulsewidth_us(obj, (int)(seconds * 1000000.0));
 210 }
 211
 212 //******************************************************************************
 213 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms)
 214 {
 215     pwmout_pulsewidth_us(obj, ms*1000);
 216 }
 217
 218 //******************************************************************************
 219 void pwmout_pulsewidth_us(pwmout_t* obj, int us)
 220 {
 221     // Check the range of the pulsewidth
 222     MBED_ASSERT((us >= 0) && (us <= (int)(SystemCoreClock/32)));
 223
 224     // Initialize period to double the pulsewidth if uninitialized
 225     if(obj->period == -1){
 226         obj->period = 2*us;
 227     }
 228
 229     // Save the pulsewidth
 230     obj->pulse_width = us;
 231
 232     // Update the register
 233     pwmout_update(obj);
 234 }