61 lines
1.5 KiB
C
61 lines
1.5 KiB
C
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/*
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ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio
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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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/**
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* TMP75 is most simple I2C device in our case. It is already useful with
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* default settings after powerup.
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* You only must read 2 sequential bytes from it.
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*/
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#include <stdlib.h>
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#include "ch.h"
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#include "hal.h"
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#include "tmp75.h"
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/* input buffer */
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static uint8_t tmp75_rx_data[TMP75_RX_DEPTH];
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/* temperature value */
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static int16_t temperature = 0;
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static i2cflags_t errors = 0;
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#define tmp75_addr 0b1001000
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/* This is main function. */
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void request_temperature(void){
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int16_t t_int = 0, t_frac = 0;
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msg_t status = RDY_OK;
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systime_t tmo = MS2ST(4);
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i2cAcquireBus(&I2CD1);
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status = i2cMasterReceiveTimeout(&I2CD1, tmp75_addr, tmp75_rx_data, 2, tmo);
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i2cReleaseBus(&I2CD1);
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if (status != RDY_OK){
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errors = i2cGetErrors(&I2CD1);
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}
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t_int = tmp75_rx_data[0] * 100;
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t_frac = (tmp75_rx_data[1] * 100) >> 8;
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temperature = t_int + t_frac;
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}
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