208 lines
6.1 KiB
C
208 lines
6.1 KiB
C
/*
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MCP9808 for ChibiOS/RT - Copyright (C) 2016 Stephane D'Alu
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#define I2C_HELPERS_AUTOMATIC_DRV TRUE
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#include "hal.h"
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#include "i2c_helpers.h"
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#include "mcp9808.h"
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// http://www.mouser.com/ds/2/268/25095A-15487.pdf
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// http://ww1.microchip.com/downloads/en/DeviceDoc/25095A.pdf
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/*===========================================================================*/
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/* Driver local definitions. */
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/*===========================================================================*/
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/* I2C Register */
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#define MCP9808_REG_CONFIG 0x01
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#define MCP9808_REG_UPPER_TEMP 0x02
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#define MCP9808_REG_LOWER_TEMP 0x03
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#define MCP9808_REG_CRIT_TEMP 0x04
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#define MCP9808_REG_AMBIENT_TEMP 0x05
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#define MCP9808_REG_MANUF_ID 0x06
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#define MCP9808_REG_DEVICE_ID 0x07
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#define MCP9808_REG_RESOLUTION 0x08
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/* Config */
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#define MCP9808_REG_CONFIG_SHUTDOWN 0x0100
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#define MCP9808_REG_CONFIG_CRITLOCKED 0x0080
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#define MCP9808_REG_CONFIG_WINLOCKED 0x0040
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#define MCP9808_REG_CONFIG_INTCLR 0x0020
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#define MCP9808_REG_CONFIG_ALERTSTAT 0x0010
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#define MCP9808_REG_CONFIG_ALERTCTRL 0x0008
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#define MCP9808_REG_CONFIG_ALERTSEL 0x0002
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#define MCP9808_REG_CONFIG_ALERTPOL 0x0002
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#define MCP9808_REG_CONFIG_ALERTMODE 0x0001
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/* Device Id */
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#define MCP9808_MANUF_ID 0x0054
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#define MCP9808_DEVICE_ID 0x0400
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/* Resolution */
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#define MCP9808_RES_2 0x00 /* 1/2 = 0.5 */
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#define MCP9808_RES_4 0x01 /* 1/4 = 0.25 */
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#define MCP9808_RES_8 0x10 /* 1/8 = 0.125 */
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#define MCP9808_RES_16 0x11 /* 1/16 = 0.0625 */
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/* Time in milli-seconds */
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#define MCP9808_DELAY_ACQUIRE_RES_2 30
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#define MCP9808_DELAY_ACQUIRE_RES_4 65
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#define MCP9808_DELAY_ACQUIRE_RES_8 130
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#define MCP9808_DELAY_ACQUIRE_RES_16 250
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/*===========================================================================*/
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/* Driver exported variables. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver local variables and types. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver local functions. */
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/*===========================================================================*/
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static inline msg_t
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_apply_config(MCP9808_drv *drv) {
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struct __attribute__((packed)) {
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uint8_t reg;
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uint16_t conf;
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} tx = { MCP9808_REG_CONFIG, cpu_to_be16(drv->cfg) };
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return i2c_send((uint8_t*)&tx, sizeof(tx));
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}
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static inline msg_t
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_decode_measure(MCP9808_drv *drv,
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uint16_t val, float *temperature) {
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/* Temperature */
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if (temperature) {
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float temp = val & 0x0fff;
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if (val & 0x1000) temp -= 0x1000;
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float factor = 16.0F;
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switch(drv->resolution) {
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case RES_2 : factor = 2.0F; break;
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case RES_4 : factor = 4.0F; break;
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case RES_8 : factor = 8.0F; break;
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case RES_16: factor = 16.0F; break;
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}
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*temperature = temp / factor;
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}
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/* Ok */
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return MSG_OK;
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}
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/*===========================================================================*/
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/* Driver exported functions. */
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/*===========================================================================*/
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void
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MCP9808_init(MCP9808_drv *drv, MCP9808_config *config) {
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drv->config = config;
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drv->cfg = 0;
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drv->resolution = RES_16; /* power up default */
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drv->state = SENSOR_INIT;
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}
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msg_t
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MCP9808_check(MCP9808_drv *drv) {
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uint16_t manuf, device;
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msg_t msg;
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if (((msg = i2c_reg_recv16_be(MCP9808_REG_MANUF_ID, &manuf )) < MSG_OK) ||
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((msg = i2c_reg_recv16_be(MCP9808_REG_DEVICE_ID, &device)) < MSG_OK))
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return msg;
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if ((manuf != MCP9808_MANUF_ID) || (device != MCP9808_DEVICE_ID))
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return SENSOR_NOTFOUND;
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return MSG_OK;
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}
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msg_t
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MCP9808_setResolution(MCP9808_drv *drv, MCP9808_resolution_t res) {
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struct __attribute__((packed)) {
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uint8_t reg;
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uint8_t resolution;
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} tx = { MCP9808_REG_RESOLUTION, res };
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msg_t msg;
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if ((msg = i2c_send((uint8_t*)&tx, sizeof(tx))) < MSG_OK)
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return msg;
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drv->resolution = res;
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return MSG_OK;
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}
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msg_t
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MCP9808_start(MCP9808_drv *drv) {
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drv->cfg &= ~(MCP9808_REG_CONFIG_SHUTDOWN);
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return _apply_config(drv);
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}
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msg_t
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MCP9808_stop(MCP9808_drv *drv) {
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drv->cfg |= (MCP9808_REG_CONFIG_SHUTDOWN);
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return _apply_config(drv);
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}
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unsigned int
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MCP9808_getAcquisitionTime(MCP9808_drv *drv) {
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switch(drv->resolution) {
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case RES_2 : return MCP9808_DELAY_ACQUIRE_RES_2;
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case RES_4 : return MCP9808_DELAY_ACQUIRE_RES_4;
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case RES_8 : return MCP9808_DELAY_ACQUIRE_RES_8;
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case RES_16: return MCP9808_DELAY_ACQUIRE_RES_16;
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}
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osalDbgAssert(false, "OOPS");
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return 0;
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}
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msg_t
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MCP9808_readMeasure(MCP9808_drv *drv,
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float *temperature) {
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msg_t msg;
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uint16_t val;
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if ((msg = i2c_reg_recv16_be(MCP9808_REG_AMBIENT_TEMP, &val)) < MSG_OK)
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return msg;
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return _decode_measure(drv, val, temperature);
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}
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msg_t
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MCP9808_readTemperature(MCP9808_drv *drv,
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float *temperature) {
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osalDbgAssert(drv->state == SENSOR_STARTED, "invalid state");
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msg_t msg;
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uint16_t val;
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if ((msg = i2c_reg_recv16_be(MCP9808_REG_AMBIENT_TEMP, &val)) < MSG_OK)
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return msg;
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return _decode_measure(drv, val, temperature);
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}
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