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099f3a4147
I2C slave might stil have something to send when ESP826 starts I2C, thus
keeping the bus stuck.
Happens e.g. when power failure/reset during transmission.
Thanks to work of drmpf there is a solution.
Implemented as separate method so as not to interfere with existing.
Usage:
Wire.begin();
if (Wire.status() != I2C_OK) Serial.writeln("Something wrong with I2C
bus that cannot be recovered. Perform power cycle or search for other
masters on bus.";
47 lines
1.6 KiB
C
47 lines
1.6 KiB
C
/*
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twi.h - Software I2C library for esp8266
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Copyright (c) 2015 Hristo Gochkov. All rights reserved.
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This file is part of the esp8266 core for Arduino environment.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef SI2C_h
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#define SI2C_h
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#include "Arduino.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define I2C_OK 0
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#define I2C_SCL_HELD_LOW 1
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#define I2C_SCL_HELD_LOW_AFTER_READ 2
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#define I2C_SDA_HELD_LOW 3
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#define I2C_SDA_HELD_LOW_AFTER_INIT 4
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void twi_init(unsigned char sda, unsigned char scl);
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void twi_stop(void);
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void twi_setClock(unsigned int freq);
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void twi_setClockStretchLimit(uint32_t limit);
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uint8_t twi_writeTo(unsigned char address, unsigned char * buf, unsigned int len, unsigned char sendStop);
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uint8_t twi_readFrom(unsigned char address, unsigned char * buf, unsigned int len, unsigned char sendStop);
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uint8_t twi_status();
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#ifdef __cplusplus
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}
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#endif
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#endif |