This is file HX711HAL.c
This file is part of HX711 routines
/*======================================================================================*/ /* Copyright (c) 2016-2019, Isaac Marino Bavaresco All rights reserved. isaacbavaresco@yahoo.com.br Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Neither the name of the author nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /*============================================================================*/ /*======================================================================================*/ #include "HX711.h" #include "HX711HAL.h" /*======================================================================================*/ #define HX711_RESET_MODE HX711_MODE_A128 /*======================================================================================*/ static hx711mode_t HX711Mode = HX711_RESET_MODE; /*======================================================================================*/ int HX711IsOn( void ) { return PDSCKQueryPin() == 0; } /*======================================================================================*/ int HX711IsReady( void ) { return HX711IsOn() && DOUTQueryPin() == 0; } /*======================================================================================*/ static signed long _HX711Read( void ) { signed long Result; int i; /* Wait until the conversion is finished */ while( !HX711IsReady() ) SystemYield(); DelayAtLeast100ns(); /* Transfer the 24 bits of the result */ for( Result = 0, i = 24; i > 0; i-- ) { /* Shift the Result variable to the left to prepare its LSBit to receive the new bit from pin DOUT. */ Result <<= 1; /* Here we must guarantee that an interrupt or context switch will not keep pin PDSCK high for more than 60 us or else the HX711 will enter power down mode, so we use a critical section. */ SystemEnterCritical(); /* Set pin PDSCK high to start a bit transfer. */ PDSCKSetPin(); /* Wait for the PDSCK high time and for pin DOUT to stabilize. */ DelayAtLeast200ns(); /* Insert the bit from DOUT into the LSBit of Result. */ Result |= DOUTQueryPin(); /* Set pin PDSCK low to finish the bit cycle. */ PDSCKClearPin(); /* Now that pin PDSCK is back to low we can exit the critical section, so interrupts or context switches can happen again. */ SystemExitCritical(); /* Wait for the PDSCK low time. */ DelayAtLeast200ns(); } for( i = HX711Mode + 1; i > 0; i-- ) { /* Here we must guarantee that an interrupt or context switch will not keep pin PDSCK high for more than 60 us or else the HX711 will enter power down mode, so we use a critical section. */ SystemEnterCritical(); PDSCKSetPin(); DelayAtLeast200ns(); PDSCKClearPin(); /* Now that pin PDSCK is back to low we can exit the critical section, so interrupts or context switches can happen again. */ SystemExitCritical(); DelayAtLeast200ns(); } /* Extend the sign bit to the MSByte */ Result = ( Result & 0x00800000 ) ? ( Result | 0xff000000 ) : Result; return Result; } /*======================================================================================*/ void HX711PowerUp( void ) { PDSCKClearPin(); if( HX711Mode != HX711_RESET_MODE ) _HX711Read(); } /*======================================================================================*/ signed long HX711Read( void ) { if( !HX711IsOn() ) HX711PowerUp(); return _HX711Read(); } /*======================================================================================*/ void HX711SetMode( hx711mode_t Mode ) { HX711Mode = Mode; if( HX711IsOn() ) _HX711Read(); } /*======================================================================================*/ void HX711PowerDown( void ) { PDSCKSetPin(); DelayAtLeast60us(); } /*======================================================================================*/ void HX711Init( void ) { HX711Mode = HX711_RESET_MODE; DOUTSetAsInput(); PDSCKSetPin(); PDSCKSetAsOutput(); HX711PowerDown(); HX711PowerUp(); } /*======================================================================================*/
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