330 lines
7.2 KiB
C
330 lines
7.2 KiB
C
/* Copyright (c) 2009 ARAGO SYSTEMS
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of the copyright holders nor the names of
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "dev/sht15.h"
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#define DATA_OUT() P3DIR |= BIT7
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#define DATA_IN() P3DIR &= ~BIT7
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#define DATA_SET() P3OUT |= BIT7; halMcuWaitUs(10)
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#define DATA_CLR() P3OUT &= ~BIT7; halMcuWaitUs(10)
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#define DATA_VAL() (P3IN & BIT7)
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#define SCK_OUT() P5DIR |= BIT4
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#define SCK_SET() P5OUT |= BIT4; halMcuWaitUs(10)
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#define SCK_CLR() P5OUT &= ~BIT4; halMcuWaitUs(10)
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/***********************************************************************************
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* @fn halMcuWaitUs
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*
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* @brief Busy wait function. Waits the specified number of microseconds. Use
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* assumptions about number of clock cycles needed for the various
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* instructions. The duration of one cycle depends on MCLK. In this HAL
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* , it is set to 8 MHz, thus 8 cycles per usec.
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*
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* NB! This function is highly dependent on architecture and compiler!
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*
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* @param uint16 usec - number of microseconds delay
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*
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* @return none
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*/
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/* #pragma optimize=none */
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void
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halMcuWaitUs(uint16_t usec) /* 5 cycles for calling */
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{
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/* The least we can wait is 3 usec: */
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/* ~1 usec for call, 1 for first compare and 1 for return */
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while(usec > 3) /* 2 cycles for compare */
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{ /* 2 cycles for jump */
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nop(); /* 1 cycles for nop */
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nop(); /* 1 cycles for nop */
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nop(); /* 1 cycles for nop */
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nop(); /* 1 cycles for nop */
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nop(); /* 1 cycles for nop */
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nop(); /* 1 cycles for nop */
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nop(); /* 1 cycles for nop */
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nop(); /* 1 cycles for nop */
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usec -= 2; /* 1 cycles for optimized decrement */
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}
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} /* 4 cycles for returning */
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/**
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SHT15/75 Driver
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!!! be advise that the SHT15 and SHT75 are not i2C compliant sensors
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they are just designed to not disturb i2C devices on a 2 wire bus
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this driver allow to drive the sensor with GPIO and delay
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*/
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/***********************************************************************************
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* @fn sht15_send_start
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*
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* @brief This function perform the start sequence asked by SHT15 and SHT75
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*
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*
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*
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* @param none
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*
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* @return none
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*/
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void
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sht15_send_start(void)
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{
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/* Sequence is to set data line to 1 then clock line to 1
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then set data line to 0, clock line to 0
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then set clock line to 1 and data line to 1
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___________ ________
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data line : _____/ \___________/
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___________ ____________
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clock line : _________/ \___/
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*/
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DATA_OUT();
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DATA_SET();
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SCK_SET();
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DATA_CLR();
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SCK_CLR();
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SCK_SET();
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DATA_SET();
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SCK_CLR();
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}
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/***********************************************************************************
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* @fn sht15_read16()
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*
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* @brief
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*
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*
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*
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* @param none
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*
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* @return uint16_t
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*/
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uint16_t
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sht15_read16(void)
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{
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uint16_t i;
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DATA_IN();
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SCK_CLR();
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uint16_t val = 0;
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for(i = 0; i < 18; i++) {
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if((i != 8) && (i != 17)) {
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SCK_SET();
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if(DATA_VAL()) {
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val |= 1;
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}
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val <<= 1;
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SCK_CLR();
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} else if(i == 8) { /* Wait for first ACK from SHT15 */
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DATA_OUT();
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DATA_CLR();
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SCK_SET();
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SCK_CLR();
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DATA_IN();
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} else if(i == 17) { /* Wait for second ACK from SHT15 */
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DATA_OUT();
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DATA_SET();
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SCK_SET();
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SCK_CLR();
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}
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}
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return val;
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}
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/***********************************************************************************
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* @fn sht15_write8
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*
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* @brief
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*
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*
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*
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* @param uint8 val
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*
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* @return none
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*/
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void
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sht15_write8(uint8_t val)
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{
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uint16_t i;
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DATA_OUT();
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for(i = 0; i < 8; i++) {
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halMcuWaitUs(4);
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SCK_CLR();
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if(val & 0x80) {
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DATA_SET();
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} else {
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DATA_CLR();
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}
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val <<= 1;
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SCK_SET();
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}
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DATA_IN();
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SCK_CLR();
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while(DATA_VAL());
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SCK_SET();
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SCK_CLR();
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}
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/***********************************************************************************
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* @fn sht15_wait_measure
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*
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* @brief
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*
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*
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*
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* @param none
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*
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* @return none
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*/
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void
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sht15_wait_measure(void)
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{
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while(DATA_VAL());
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}
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/***********************************************************************************
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* @fn sht15_init
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*
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* @brief
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*
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*
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*
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* @param none
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*
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* @return none
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*/
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void
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sht15_init(void)
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{
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/* DATA and SCK lines are I/O */
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P3SEL &= ~BIT7;
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P5SEL &= ~BIT4;
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/* Set SCK and DATA as output */
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DATA_OUT();
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SCK_OUT();
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DATA_SET();
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SCK_SET();
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}
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/***********************************************************************************
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* @fn sht15_measure_temp
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*
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* @brief
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*
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*
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*
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* @param none
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*
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* @return none
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*/
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void
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sht15_measure_temp(void)
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{
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sht15_send_start();
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sht15_write8(3);
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}
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/***********************************************************************************
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* @fn sht15_measure_hum
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*
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* @brief
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*
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*
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*
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* @param none
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*
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* @return none
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*/
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void sht15_measure_hum()
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{
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sht15_send_start();
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sht15_write8(5);
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}
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/***********************************************************************************
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* @fn sht15_read_status
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*
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* @brief
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*
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*
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*
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* @param none
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*
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* @return none
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*/
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void
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sht15_read_status()
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{
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sht15_send_start();
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sht15_write8(7);
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}
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/***********************************************************************************
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* @fn sht15_write_status
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*
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* @brief
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*
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*
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*
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* @param none
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*
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* @return none
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*/
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void
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sht15_write_status(void)
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{
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sht15_send_start();
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sht15_write8(6);
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}
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/***********************************************************************************
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* @fn sht15_soft_reset
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*
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* @brief
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*
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*
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*
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* @param none
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*
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* @return none
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*/
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void
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sht15_soft_reset(void)
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{
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sht15_send_start();
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sht15_write8(30);
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}
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