Merge pull request #201 from toyowata/master

Added PwmOut for LPC1549 target

Author: emilmont

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC15XX/device.h

@@ -40,7 +40,7 @@
 
 #define DEVICE_ETHERNET         0
 
-#define DEVICE_PWMOUT           0
+#define DEVICE_PWMOUT           1
 
 #define DEVICE_SEMIHOST         0
 #define DEVICE_LOCALFILESYSTEM  0

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC15XX/objects.h

@@ -29,6 +29,11 @@ struct gpio_irq_s {
     uint32_t ch;
 };
 
+struct pwmout_s {
+     LPC_SCT0_Type* pwm;
+     uint32_t pwm_ch;
+};
+
 struct serial_s {
     LPC_USART0_Type *uart;
     unsigned char index;

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC15XX/pwmout_api.c

@@ -0,0 +1,169 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 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 "pwmout_api.h"
+#include "cmsis.h"
+#include "pinmap.h"
+#include "error.h"
+
+static LPC_SCT0_Type *SCTs[4] = {
+    (LPC_SCT0_Type*)LPC_SCT0,
+    (LPC_SCT0_Type*)LPC_SCT1,
+    (LPC_SCT0_Type*)LPC_SCT2,
+    (LPC_SCT0_Type*)LPC_SCT3,
+};
+
+// bit flags for used SCTs
+static unsigned char sct_used = 0;
+static int get_available_sct(void) {
+    int i;
+    // start from 1, since 0 is used by ticker at the moment
+    for (i=1; i<4; i++) {
+        if ((sct_used & (1 << i)) == 0)
+            return i;
+    }
+    return -1;
+}
+
+void pwmout_init(pwmout_t* obj, PinName pin) {
+	if (pin == (uint32_t)NC)
+		error("PwmOut pin mapping failed");
+	
+    int sct_n = get_available_sct();
+    if (sct_n == -1) {
+        error("No available SCT");
+    }
+    
+    sct_used |= (1 << sct_n);
+    obj->pwm =  SCTs[sct_n];
+    obj->pwm_ch = sct_n;
+
+    LPC_SCT0_Type* pwm = obj->pwm;
+
+    // Enable the SCT clock
+    LPC_SYSCON->SYSAHBCLKCTRL1 |= (1 << (obj->pwm_ch + 2));
+
+    // Clear peripheral reset the SCT:
+    LPC_SYSCON->PRESETCTRL1 |=  (1 << (obj->pwm_ch + 2));
+    LPC_SYSCON->PRESETCTRL1 &= ~(1 << (obj->pwm_ch + 2));
+    
+    switch(obj->pwm_ch) {
+    	case 1:
+            // SCT1_OUT0
+            LPC_SWM->PINASSIGN[8] &= ~0x000000FF;
+            LPC_SWM->PINASSIGN[8] |= (pin);
+    		break;
+    	case 2:
+            // SCT2_OUT0
+            LPC_SWM->PINASSIGN[8] &= ~0xFF000000;
+            LPC_SWM->PINASSIGN[8] |= (pin << 24);
+    		break;
+    	case 3:
+            // SCT3_OUT0
+            LPC_SWM->PINASSIGN[9] &= ~0x00FF0000;
+            LPC_SWM->PINASSIGN[9] |= (pin << 16);
+    		break;
+    	default:
+    		break;
+    }
+    
+    // Two 16-bit counters, autolimit
+    pwm->CONFIG &= ~(0x1);
+    pwm->CONFIG |= (1 << 17);
+    
+    // halt and clear the counter
+    pwm->CTRL |= (1 << 2) | (1 << 3);
+    
+    // System Clock -> us_ticker (1)MHz
+    pwm->CTRL &= ~(0x7F << 5);
+    pwm->CTRL |= (((SystemCoreClock/1000000 - 1) & 0x7F) << 5);
+    
+    // Match reload register
+    pwm->MATCHREL0 = 20000; // 20ms
+    pwm->MATCHREL1 = (pwm->MATCHREL0 / 4); // 50% duty
+    
+    pwm->OUT0_SET = (1 << 0); // event 0
+    pwm->OUT0_CLR = (1 << 1); // event 1
+
+	pwm->EV0_CTRL  = (1 << 12);
+	pwm->EV0_STATE = 0xFFFFFFFF;
+	pwm->EV1_CTRL  = (1 << 12) | (1 << 0);
+	pwm->EV1_STATE = 0xFFFFFFFF;
+
+    // unhalt the counter:
+    //    - clearing bit 2 of the CTRL register
+    pwm->CTRL &= ~(1 << 2);
+
+    // default to 20ms: standard for servos, and fine for e.g. brightness control
+    pwmout_period_ms(obj, 20);
+    pwmout_write    (obj, 0);
+}
+
+void pwmout_free(pwmout_t* obj) {
+    // Disable the SCT clock
+    LPC_SYSCON->SYSAHBCLKCTRL1 &= ~(1 << (obj->pwm_ch + 2));
+    sct_used &= ~(1 << obj->pwm_ch);
+}
+
+void pwmout_write(pwmout_t* obj, float value) {
+    LPC_SCT0_Type* pwm = obj->pwm;
+    if (value < 0.0f) {
+        value = 0.0;
+    } else if (value > 1.0f) {
+        value = 1.0;
+    }
+    uint32_t t_off = pwm->MATCHREL0 - (uint32_t)((float)(pwm->MATCHREL0) * value);
+    uint32_t t_on = (uint32_t)((float)(pwm->MATCHREL0) * value);
+    pwm->MATCHREL1 = t_on;
+}
+
+float pwmout_read(pwmout_t* obj) {
+    uint32_t t_off = obj->pwm->MATCHREL0;
+    uint32_t t_on  = obj->pwm->MATCHREL1;
+	float v = (float)t_on/(float)t_off;
+    return (v > 1.0f) ? (1.0f) : (v);
+}
+
+void pwmout_period(pwmout_t* obj, float seconds) {
+    pwmout_period_us(obj, seconds * 1000000.0f);
+}
+
+void pwmout_period_ms(pwmout_t* obj, int ms) {
+    pwmout_period_us(obj, ms * 1000);
+}
+
+// Set the PWM period, keeping the duty cycle the same.
+void pwmout_period_us(pwmout_t* obj, int us) {
+    LPC_SCT0_Type* pwm = obj->pwm;
+    uint32_t t_off = pwm->MATCHREL0;
+    uint32_t t_on  = pwm->MATCHREL1;
+	float v = (float)t_on/(float)t_off;
+    pwm->MATCHREL0 = (uint64_t)us;
+    pwm->MATCHREL1 = (uint64_t)((float)us * (float)v);
+}
+
+void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
+    pwmout_pulsewidth_us(obj, 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) {
+    obj->pwm->MATCHREL1 = (uint64_t)us;
+}
+