Lee Kai Xuan / mbed-os

mbed-os

Fork of mbed-os by erkin yucel

targets/TARGET_NXP/TARGET_LPC176X/analogout_api.c@0:f269e3021894, 2016-10-23 (annotated)

Committer:
elessair
Date:
Sun Oct 23 15:10:02 2016 +0000
Revision:
0:f269e3021894
Initial commit

Who changed what in which revision?

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elessair 0:f269e3021894 1 /* mbed Microcontroller Library
elessair 0:f269e3021894 2 * Copyright (c) 2006-2013 ARM Limited
elessair 0:f269e3021894 3 *
elessair 0:f269e3021894 4 * Licensed under the Apache License, Version 2.0 (the "License");
elessair 0:f269e3021894 5 * you may not use this file except in compliance with the License.
elessair 0:f269e3021894 6 * You may obtain a copy of the License at
elessair 0:f269e3021894 7 *
elessair 0:f269e3021894 8 * http://www.apache.org/licenses/LICENSE-2.0
elessair 0:f269e3021894 9 *
elessair 0:f269e3021894 10 * Unless required by applicable law or agreed to in writing, software
elessair 0:f269e3021894 11 * distributed under the License is distributed on an "AS IS" BASIS,
elessair 0:f269e3021894 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
elessair 0:f269e3021894 13 * See the License for the specific language governing permissions and
elessair 0:f269e3021894 14 * limitations under the License.
elessair 0:f269e3021894 15 */
elessair 0:f269e3021894 16 #include "mbed_assert.h"
elessair 0:f269e3021894 17 #include "analogout_api.h"
elessair 0:f269e3021894 18
elessair 0:f269e3021894 19 #include "cmsis.h"
elessair 0:f269e3021894 20 #include "pinmap.h"
elessair 0:f269e3021894 21
elessair 0:f269e3021894 22 static const PinMap PinMap_DAC[] = {
elessair 0:f269e3021894 23 {P0_26, DAC_0, 2},
elessair 0:f269e3021894 24 {NC , NC , 0}
elessair 0:f269e3021894 25 };
elessair 0:f269e3021894 26
elessair 0:f269e3021894 27 void analogout_init(dac_t *obj, PinName pin) {
elessair 0:f269e3021894 28 obj->dac = (DACName)pinmap_peripheral(pin, PinMap_DAC);
elessair 0:f269e3021894 29 MBED_ASSERT(obj->dac != (DACName)NC);
elessair 0:f269e3021894 30
elessair 0:f269e3021894 31 // power is on by default, set DAC clk divider is /4
elessair 0:f269e3021894 32 LPC_SC->PCLKSEL0 &= ~(0x3 << 22);
elessair 0:f269e3021894 33
elessair 0:f269e3021894 34 // map out (must be done before accessing registers)
elessair 0:f269e3021894 35 pinmap_pinout(pin, PinMap_DAC);
elessair 0:f269e3021894 36
elessair 0:f269e3021894 37 analogout_write_u16(obj, 0);
elessair 0:f269e3021894 38 }
elessair 0:f269e3021894 39
elessair 0:f269e3021894 40 void analogout_free(dac_t *obj) {}
elessair 0:f269e3021894 41
elessair 0:f269e3021894 42 static inline void dac_write(int value) {
elessair 0:f269e3021894 43 value &= 0x3FF; // 10-bit
elessair 0:f269e3021894 44
elessair 0:f269e3021894 45 // Set the DAC output
elessair 0:f269e3021894 46 LPC_DAC->DACR = (0 << 16) // bias = 0
elessair 0:f269e3021894 47 | (value << 6);
elessair 0:f269e3021894 48 }
elessair 0:f269e3021894 49
elessair 0:f269e3021894 50 static inline int dac_read() {
elessair 0:f269e3021894 51 return (LPC_DAC->DACR >> 6) & 0x3FF;
elessair 0:f269e3021894 52 }
elessair 0:f269e3021894 53
elessair 0:f269e3021894 54 void analogout_write(dac_t *obj, float value) {
elessair 0:f269e3021894 55 if (value < 0.0f) {
elessair 0:f269e3021894 56 dac_write(0);
elessair 0:f269e3021894 57 } else if (value > 1.0f) {
elessair 0:f269e3021894 58 dac_write(0x3FF);
elessair 0:f269e3021894 59 } else {
elessair 0:f269e3021894 60 dac_write(value * (float)0x3FF);
elessair 0:f269e3021894 61 }
elessair 0:f269e3021894 62 }
elessair 0:f269e3021894 63
elessair 0:f269e3021894 64 void analogout_write_u16(dac_t *obj, uint16_t value) {
elessair 0:f269e3021894 65 dac_write(value >> 6); // 10-bit
elessair 0:f269e3021894 66 }
elessair 0:f269e3021894 67
elessair 0:f269e3021894 68 float analogout_read(dac_t *obj) {
elessair 0:f269e3021894 69 uint32_t value = dac_read();
elessair 0:f269e3021894 70 return (float)value * (1.0f / (float)0x3FF);
elessair 0:f269e3021894 71 }
elessair 0:f269e3021894 72
elessair 0:f269e3021894 73 uint16_t analogout_read_u16(dac_t *obj) {
elessair 0:f269e3021894 74 uint32_t value = dac_read(); // 10-bit
elessair 0:f269e3021894 75 return (value << 6) | ((value >> 4) & 0x003F);
elessair 0:f269e3021894 76 }