Diff: targets/TARGET_Maxim/TARGET_MAX32620/pwmout_api.c

Revision:

149:156823d33999

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_Maxim/TARGET_MAX32620/pwmout_api.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,211 @@
+/*******************************************************************************
+ * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
+ * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the name of Maxim Integrated
+ * Products, Inc. shall not be used except as stated in the Maxim Integrated
+ * Products, Inc. Branding Policy.
+ *
+ * The mere transfer of this software does not imply any licenses
+ * of trade secrets, proprietary technology, copyrights, patents,
+ * trademarks, maskwork rights, or any other form of intellectual
+ * property whatsoever. Maxim Integrated Products, Inc. retains all
+ * ownership rights.
+ *******************************************************************************
+ */
+
+#include "mbed_assert.h"
+#include "cmsis.h"
+#include "pwmout_api.h"
+#include "pinmap.h"
+#include "clkman_regs.h"
+#include "PeripheralPins.h"
+
+//******************************************************************************
+void pwmout_init(pwmout_t* obj, PinName pin)
+{
+    // Make sure the pin is free for GPIO use
+    unsigned int port = (unsigned int)pin >> PORT_SHIFT;
+    unsigned int port_pin = (unsigned int)pin & ~(0xFFFFFFFF << PORT_SHIFT);
+    MBED_ASSERT(MXC_GPIO->free[port] & (0x1 << port_pin));
+
+    int i = 0;
+    PinMap pwm = PinMap_PWM[0];
+
+    // Check if there is a pulse train already active on this port
+    int pin_func = (MXC_GPIO->func_sel[port] & (0xF << (port_pin*4))) >> (port_pin*4);
+    MBED_ASSERT((pin_func < 1) || (pin_func > 3));
+
+    // Search through PinMap_PWM to find the pin
+    while (pwm.pin != pin) {
+        pwm = PinMap_PWM[++i];
+    }
+
+    // Find a free PT instance on this pin
+    while (pwm.pin == pin) {
+
+        // Check to see if this PT instance is free
+        if (((mxc_pt_regs_t*)pwm.peripheral)->rate_length & MXC_F_PT_RATE_LENGTH_MODE) {
+            break;
+        }
+
+        pwm = PinMap_PWM[++i];
+
+        // Raise an assertion if we can not allocate another PT instance.
+        MBED_ASSERT(pwm.pin == pin);
+    }
+
+    // Enable the clock
+    MXC_CLKMAN->sys_clk_ctrl_7_pt = MXC_S_CLKMAN_CLK_SCALE_DIV_1;
+
+    // Set the obj pointer to the propper PWM instance
+    obj->pwm = (mxc_pt_regs_t*)pwm.peripheral;
+
+    // Initialize object period and pulse width
+    obj->period = -1;
+    obj->pulse_width = -1;
+
+    // Disable the output
+    obj->pwm->train = 0x0;
+    obj->pwm->rate_length = 0x0;
+
+    // Configure the pin
+    pin_mode(pin, (PinMode)PullNone);
+    pin_function(pin, pwm.function);
+
+    // default to 20ms: standard for servos, and fine for e.g. brightness control
+    pwmout_period_us(obj, 20000);
+    pwmout_write    (obj, 0);
+
+    // Set the drive mode to normal
+    MXC_SET_FIELD(&MXC_GPIO->out_mode[port], (0x7 << (port_pin*4)), (MXC_V_GPIO_OUT_MODE_NORMAL << (port_pin*4)));
+
+    // Enable this PWM channel
+    MXC_PTG->enable |= (1 << MXC_PT_GET_IDX(obj->pwm));
+}
+
+//******************************************************************************
+void pwmout_free(pwmout_t* obj)
+{
+    // Set the registers to the reset value
+    obj->pwm->train = 0;
+    obj->pwm->rate_length = 0x08000000;
+}
+
+//******************************************************************************
+static void pwmout_update(pwmout_t* obj)
+{
+    // Calculate and set the divider ratio
+    int div = (obj->period * (SystemCoreClock/1000000))/32;
+    if (div < 2) {
+        div = 2;
+    }
+    MXC_SET_FIELD(&obj->pwm->rate_length, MXC_F_PT_RATE_LENGTH_RATE_CONTROL, div);
+
+    // Change the duty cycle to adjust the pulse width
+    obj->pwm->train = (0xFFFFFFFF << (32-((32*obj->pulse_width)/obj->period)));
+}
+
+
+//******************************************************************************
+void pwmout_write(pwmout_t* obj, float percent)
+{
+    // Saturate percent if outside of range
+    if (percent < 0.0f) {
+        percent = 0.0f;
+    } else if(percent > 1.0f) {
+        percent = 1.0f;
+    }
+
+    // Resize the pulse width to set the duty cycle
+    pwmout_pulsewidth_us(obj, (int)(percent*obj->period));
+}
+
+//******************************************************************************
+float pwmout_read(pwmout_t* obj)
+{
+    // Check for when pulsewidth or period equals 0
+    if ((obj->pulse_width == 0) || (obj->period == 0)) {
+        return 0;
+    }
+
+    // Return the duty cycle
+    return ((float)obj->pulse_width / (float)obj->period);
+}
+
+//******************************************************************************
+void pwmout_period(pwmout_t* obj, float seconds)
+{
+    pwmout_period_us(obj, (int)(seconds * 1000000.0f));
+}
+
+//******************************************************************************
+void pwmout_period_ms(pwmout_t* obj, int ms)
+{
+    pwmout_period_us(obj, ms*1000);
+}
+
+//******************************************************************************
+void pwmout_period_us(pwmout_t* obj, int us)
+{
+    // Check the range of the period
+    MBED_ASSERT((us >= 0) && (us <= (int)(SystemCoreClock/32)));
+
+    // Set pulse width to half the period if uninitialized
+    if (obj->pulse_width == -1) {
+        obj->pulse_width = us/2;
+    }
+
+    // Save the period
+    obj->period = us;
+
+    // Update the registers
+    pwmout_update(obj);
+}
+
+//******************************************************************************
+void pwmout_pulsewidth(pwmout_t* obj, float seconds)
+{
+    pwmout_pulsewidth_us(obj, (int)(seconds * 1000000.0f));
+}
+
+//******************************************************************************
+void pwmout_pulsewidth_ms(pwmout_t* obj, int ms)
+{
+    pwmout_pulsewidth_us(obj, ms*1000);
+}
+
+//******************************************************************************
+void pwmout_pulsewidth_us(pwmout_t* obj, int us)
+{
+    // Check the range of the pulsewidth
+    MBED_ASSERT((us >= 0) && (us <= (int)(SystemCoreClock/32)));
+
+    // Initialize period to double the pulsewidth if uninitialized
+    if (obj->period == -1) {
+        obj->period = 2*us;
+    }
+
+    // Save the pulsewidth
+    obj->pulse_width = us;
+
+    // Update the register
+    pwmout_update(obj);
+}