Diff: targets/TARGET_Atmel/TARGET_SAM_CortexM0P/pwmout_api.c

Revision:

149:156823d33999

Parent:

64:41a834223ea3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_Atmel/TARGET_SAM_CortexM0P/pwmout_api.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,302 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "mbed_assert.h"
+#include "pwmout_api.h"
+
+#include "cmsis.h"
+
+#include "pinmap_function.h"
+
+/* Prescaler values for TCC Module */
+const uint32_t tcc_prescaler[] = {
+    TCC_CLOCK_PRESCALER_DIV1,
+    TCC_CLOCK_PRESCALER_DIV2,
+    TCC_CLOCK_PRESCALER_DIV4,
+    TCC_CLOCK_PRESCALER_DIV8,
+    TCC_CLOCK_PRESCALER_DIV16,
+    TCC_CLOCK_PRESCALER_DIV64,
+    TCC_CLOCK_PRESCALER_DIV256,
+    TCC_CLOCK_PRESCALER_DIV1024
+};
+
+/* Max count limits of TCC Modules */
+extern const uint32_t _tcc_maxs[TCC_INST_NUM];
+
+/** Set the period of PWM object (will not update the waveform)
+ *
+ * @param[in] obj        The PWM object whose period is to be updated
+ * @param[in] period_us  Period in microseconds
+ * @return    void
+ */
+static void pwmout_set_period(pwmout_t* obj, int period_us)
+{
+    uint8_t i;
+    uint32_t freq_hz;
+    uint32_t div_freq;
+    double us_per_cycle;
+    uint64_t max_period = 0;
+    uint32_t us_period = period_us;
+
+    /* Sanity check arguments */
+    MBED_ASSERT(obj);
+
+    /* TCC instance index */
+    uint8_t module_index = _tcc_get_inst_index(obj->tcc.hw);
+
+    uint32_t count_max  = _tcc_maxs[module_index];
+
+    freq_hz = system_gclk_gen_get_hz(obj->clock_source);
+
+    for (i=0; i<sizeof(tcc_prescaler); i++) {
+        div_freq = freq_hz >> tcc_prescaler[i];
+        if (!div_freq) break;
+        us_per_cycle = 1000000.00 / div_freq;
+        max_period = us_per_cycle * count_max;
+        if (max_period >= us_period) {
+            obj->clock_prescaler = (enum tc_clock_prescaler)tcc_prescaler[i];
+            obj->period = us_period / us_per_cycle;
+            obj->us_per_cycle = us_per_cycle;
+            break;
+        }
+    }
+}
+
+/** Initialize PWM Module with updated values
+ *
+ * @param[in][out] obj  The PWM object to initialize
+ * @return         non-zero if success
+ */
+bool pwmout_init_hw(pwmout_t* obj)
+{
+    uint32_t mux_func = (uint32_t)NC;
+    uint32_t pwm = (uint32_t)NC;
+    PinName pin;
+    uint32_t ch_index = (uint32_t)NC;
+    struct tcc_config config_tcc;
+    uint32_t tcc_channel = (uint32_t)NC;
+
+    /* Sanity check arguments */
+    MBED_ASSERT(obj);
+
+    pin = obj->pin;
+    pwm = pinmap_peripheral(pin, PinMap_PWM);
+    if (pwm == (uint32_t)NC) return 0; /* Pin not supported */
+
+    mux_func = pinmap_function(pin, PinMap_PWM);
+    ch_index = pinmap_channel_pwm(pin, (PWMName) pwm);
+    if ((mux_func == (uint32_t)NC) || (ch_index == (uint32_t)NC)) {
+        /* Pin not supported */
+        return 0;
+    }
+    if ((ch_index == 0) || (ch_index == 4)) {
+        tcc_channel = 0;
+    } else if ((ch_index == 1) || (ch_index == 5)) {
+        tcc_channel = 1;
+    } else if ((ch_index == 2) || (ch_index == 6)) {
+        tcc_channel = 2;
+    } else if ((ch_index == 3) || (ch_index == 7)) {
+        tcc_channel = 3;
+    }
+
+    tcc_get_config_defaults(&config_tcc, (Tcc*)pwm);
+
+    config_tcc.counter.clock_source = obj->clock_source;
+    config_tcc.counter.clock_prescaler = (enum tcc_clock_prescaler)obj->clock_prescaler;
+
+    config_tcc.counter.period = obj->period;
+    config_tcc.compare.wave_generation = TCC_WAVE_GENERATION_SINGLE_SLOPE_PWM;
+    config_tcc.compare.match[tcc_channel] = obj->period * obj->duty_cycle;
+
+    config_tcc.pins.enable_wave_out_pin[ch_index] = true;
+    config_tcc.pins.wave_out_pin[ch_index]        = pin;
+    config_tcc.pins.wave_out_pin_mux[ch_index]    = mux_func;
+
+    return (STATUS_OK == tcc_init(&obj->tcc, (Tcc*)pwm, &config_tcc));
+
+}
+
+/** Initialize PWM Module
+ *
+ * @param[in][out] obj  The PWM object to initialize
+ * @return         void
+ */
+void pwmout_init(pwmout_t* obj, PinName pin)
+{
+    /* Sanity check arguments */
+    MBED_ASSERT(obj);
+
+    if ((uint32_t)NC == pinmap_peripheral(pin, PinMap_PWM)) {
+        /* Pin not supported */
+        return;
+    }
+
+    obj->pin = pin;
+    obj->period = 0xFFFF;
+    obj->duty_cycle = 1;
+    obj->clock_source = GCLK_GENERATOR_0; /* 8Mhz input clock */
+    obj->clock_prescaler = (enum tc_clock_prescaler)TCC_CLOCK_PRESCALER_DIV8; /* Default to 1MHz for 8Mhz input clock */
+
+    /* Update the changes */
+    if (pwmout_init_hw(obj)) {
+        /* Enable PWM Module */
+        tcc_enable(&obj->tcc);
+    }
+
+}
+
+/** Free the PWM Module
+ *
+ * @param[in] obj  The PWM object to free
+ * @return    void
+ */
+void pwmout_free(pwmout_t* obj)
+{
+    /* Sanity check arguments */
+    MBED_ASSERT(obj);
+
+    tcc_disable(&obj->tcc);
+}
+
+/** Set the duty cycle of PWM Waveform
+ *
+ * @param[in] obj    The PWM object
+ * @param[in] value  New duty cycle to be set
+ * @return    void
+ */
+void pwmout_write(pwmout_t* obj, float value)
+{
+    /* Sanity check arguments */
+    MBED_ASSERT(obj);
+
+    if (value < 0.0f) {
+        value = 0;
+    } else if (value > 1.0f) {
+        value = 1;
+    }
+
+    /* Modify the pulse width keeping period same */
+    obj->duty_cycle = value;
+
+    /* Disable PWM Module */
+    tcc_disable(&obj->tcc);
+
+    /* Update the changes */
+    if (pwmout_init_hw(obj)) {
+        /* Enable PWM Module */
+        tcc_enable(&obj->tcc);
+    }
+}
+
+/** Get the duty cycle of PWM Waveform
+ *
+ * @param[in] obj  The PWM object
+ * @return    Current duty cycle
+ */
+float pwmout_read(pwmout_t* obj)
+{
+    /* Sanity check arguments */
+    MBED_ASSERT(obj);
+
+    return obj->duty_cycle;
+}
+
+/** Set the period of PWM Waveform
+ *
+ * @param[in] obj      The PWM object
+ * @param[in] seconds  New period in seconds
+ * @return           void
+ */
+void pwmout_period(pwmout_t* obj, float seconds)
+{
+    pwmout_period_us(obj, seconds * 1000000.0f);
+}
+
+/** Set the period of PWM Waveform
+ *
+ * @param[in] obj    The PWM object
+ * @param[in] value  New period in milliseconds
+ * @return           void
+ */
+void pwmout_period_ms(pwmout_t* obj, int ms)
+{
+    pwmout_period_us(obj, ms * 1000);
+}
+
+/** Set the period of PWM Waveform
+ *
+ * @param[in] obj  The PWM object
+ * @param[in] us   New period in microseconds
+ * @return    void
+ */
+void pwmout_period_us(pwmout_t* obj, int us)
+{
+    /* Sanity check arguments */
+    MBED_ASSERT(obj);
+
+    /* Disable PWM Module */
+    tcc_disable(&obj->tcc);
+
+    /* TODO: Find and set the period */
+    pwmout_set_period(obj, us);
+
+    /* Update the changes */
+    if (pwmout_init_hw(obj)) {
+        /* Enable PWM Module */
+        tcc_enable(&obj->tcc);
+    }
+}
+
+/** Set the pulse width of PWM Waveform
+ *
+ * @param[in] obj      The PWM object
+ * @param[in] seconds  New pulse width in seconds
+ * @return    void
+ */
+void pwmout_pulsewidth(pwmout_t* obj, float seconds)
+{
+    pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
+}
+
+/** Set the pulse width of PWM Waveform
+ *
+ * @param[in] obj  The PWM object
+ * @param[in] ms   New pulse width in milliseconds
+ * @return    void
+ */
+void pwmout_pulsewidth_ms(pwmout_t* obj, int ms)
+{
+    pwmout_pulsewidth_us(obj, ms * 1000);
+}
+
+/** Set the pulse width of PWM Waveform
+ *
+ * @param[in] obj  The PWM object
+ * @param[in] us   New pulse width in microseconds
+ * @return    void
+ */
+void pwmout_pulsewidth_us(pwmout_t* obj, int us)
+{
+    /* Sanity check arguments */
+    MBED_ASSERT(obj);
+
+    uint32_t us_pulse = us;
+
+    /* Find the new duty cycle */
+    double duty_cycle = us_pulse / ((double)obj->period * obj->us_per_cycle);
+
+    /* This call updates pulse width as well as period */
+    pwmout_write(obj, duty_cycle);
+}