mbed-os/targets/TARGET_NXP/TARGET_LPC43XX/analogout_api.c

92 lines
2.3 KiB
C

/* 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.
*
* Ported to NXP LPC43XX by Micromint USA <support@micromint.com>
*/
#include "mbed_assert.h"
#include "analogout_api.h"
#include "cmsis.h"
#include "pinmap.h"
#include "mbed_error.h"
#include "gpio_api.h"
static const PinMap PinMap_DAC[] = {
#ifdef TARGET_LPC4337
{P4_3, DAC_0, 0},
#else
{P4_4, DAC_0, 0},
#endif
{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);
// Reset pin function to GPIO
gpio_set(pin);
// Select DAC on analog function select register in SCU
LPC_SCU->ENAIO[2] |= 1; // Sets pin as DAC
// Set bias=0 for maximum DAC update rate (1 MHz)
LPC_DAC->CR &= ~DAC_BIAS_EN;
// Enable DAC and DMA
LPC_DAC->CTRL |= DAC_DMA_ENA;
analogout_write_u16(obj, 0);
}
void analogout_free(dac_t *obj) {}
static inline void dac_write(int value) {
// Set the DAC output
LPC_DAC->CR = DAC_SET(value);
}
static inline int dac_read() {
return (DAC_GET(LPC_DAC->CR));
}
void analogout_write(dac_t *obj, float value) {
if (value < 0.0f) {
dac_write(0);
} else if (value > 1.0f) {
dac_write(DAC_RANGE);
} else {
dac_write(value * (float)DAC_RANGE);
}
}
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)DAC_RANGE);
}
uint16_t analogout_read_u16(dac_t *obj) {
uint32_t value = dac_read(); // 10-bit
return (value << 6) | ((value >> 4) & 0x003F);
}
const PinMap *analogout_pinmap()
{
return PinMap_DAC;
}