Diff: targets/TARGET_NXP/TARGET_LPC176X/analogout_api.c

Revision:

0:f269e3021894

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC176X/analogout_api.c	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,76 @@
+/* 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 "mbed_assert.h"
+#include "analogout_api.h"
+
+#include "cmsis.h"
+#include "pinmap.h"
+
+static const PinMap PinMap_DAC[] = {
+    {P0_26, DAC_0, 2},
+    {NC   , NC   , 0}
+};
+
+void analogout_init(dac_t *obj, PinName pin) {
+    obj->dac = (DACName)pinmap_peripheral(pin, PinMap_DAC);
+    MBED_ASSERT(obj->dac != (DACName)NC);
+    
+    // power is on by default, set DAC clk divider is /4
+    LPC_SC->PCLKSEL0 &= ~(0x3 << 22);
+    
+    // map out (must be done before accessing registers)
+    pinmap_pinout(pin, PinMap_DAC);
+    
+    analogout_write_u16(obj, 0);
+}
+
+void analogout_free(dac_t *obj) {}
+
+static inline void dac_write(int value) {
+    value &= 0x3FF; // 10-bit
+    
+    // Set the DAC output
+    LPC_DAC->DACR = (0 << 16)       // bias = 0
+                  | (value << 6);
+}
+
+static inline int dac_read() {
+    return (LPC_DAC->DACR >> 6) & 0x3FF;
+}
+
+void analogout_write(dac_t *obj, float value) {
+    if (value < 0.0f) {
+        dac_write(0);
+    } else if (value > 1.0f) {
+        dac_write(0x3FF);
+    } else {
+        dac_write(value * (float)0x3FF);
+    }
+}
+
+void analogout_write_u16(dac_t *obj, uint16_t value) {
+    dac_write(value >> 6); // 10-bit
+}
+
+float analogout_read(dac_t *obj) {
+    uint32_t value = dac_read();
+    return (float)value * (1.0f / (float)0x3FF);
+}
+
+uint16_t analogout_read_u16(dac_t *obj) {
+    uint32_t value = dac_read(); // 10-bit
+    return (value << 6) | ((value >> 4) & 0x003F);
+}