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433 lines
10 KiB
433 lines
10 KiB
/*
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si2c.c - Software I2C library for ESP31B
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Copyright (c) 2015 Hristo Gochkov. All rights reserved.
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This file is part of the ESP31B 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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#include <stdint.h>
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#include <stdbool.h>
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#include "twi.h"
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#include "soc/gpio_reg.h"
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#include "soc/gpio_struct.h"
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#include "soc/io_mux_reg.h"
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#include "driver/rtc_io.h"
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#include <stdio.h>
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#define LOW 0x0
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#define HIGH 0x1
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//GPIO FUNCTIONS
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#define INPUT 0x01
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#define OUTPUT 0x02
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#define PULLUP 0x04
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#define INPUT_PULLUP 0x05
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#define PULLDOWN 0x08
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#define INPUT_PULLDOWN 0x09
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#define OPEN_DRAIN 0x10
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#define OUTPUT_OPEN_DRAIN 0x12
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#define SPECIAL 0xF0
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#define FUNCTION_1 0x00
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#define FUNCTION_2 0x20
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#define FUNCTION_3 0x40
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#define FUNCTION_4 0x60
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#define FUNCTION_5 0x80
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#define FUNCTION_6 0xA0
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#define ESP_REG(addr) *((volatile uint32_t *)(addr))
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const uint8_t pin_to_mux[40] = { 0x44, 0x88, 0x40, 0x84, 0x48, 0x6c, 0x60, 0x64, 0x68, 0x54, 0x58, 0x5c, 0x34, 0x38, 0x30, 0x3c, 0x4c, 0x50, 0x70, 0x74, 0x78, 0x7c, 0x80, 0x8c, 0, 0x24, 0x28, 0x2c, 0, 0, 0, 0, 0x1c, 0x20, 0x14, 0x18, 0x04, 0x08, 0x0c, 0x10};
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static void pinMode(uint8_t pin, uint8_t mode)
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{
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if(pin >= 40) {
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return;
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}
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uint32_t rtc_reg = rtc_gpio_desc[pin].reg;
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//RTC pins PULL settings
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if(rtc_reg) {
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//lock rtc
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ESP_REG(rtc_reg) = ESP_REG(rtc_reg) & ~(rtc_gpio_desc[pin].mux);
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if(mode & PULLUP) {
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ESP_REG(rtc_reg) = (ESP_REG(rtc_reg) | rtc_gpio_desc[pin].pullup) & ~(rtc_gpio_desc[pin].pulldown);
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} else if(mode & PULLDOWN) {
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ESP_REG(rtc_reg) = (ESP_REG(rtc_reg) | rtc_gpio_desc[pin].pulldown) & ~(rtc_gpio_desc[pin].pullup);
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} else {
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ESP_REG(rtc_reg) = ESP_REG(rtc_reg) & ~(rtc_gpio_desc[pin].pullup | rtc_gpio_desc[pin].pulldown);
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}
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//unlock rtc
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}
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uint32_t pinFunction = 0, pinControl = 0;
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//lock gpio
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if(mode & INPUT) {
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if(pin < 32) {
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GPIO.enable_w1tc = BIT(pin);
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} else {
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GPIO.enable1_w1tc.val = BIT(pin - 32);
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}
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} else if(mode & OUTPUT) {
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if(pin > 33) {
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//unlock gpio
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return;//pins above 33 can be only inputs
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} else if(pin < 32) {
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GPIO.enable_w1ts = BIT(pin);
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} else {
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GPIO.enable1_w1ts.val = BIT(pin - 32);
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}
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}
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if(mode & PULLUP) {
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pinFunction |= FUN_PU;
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} else if(mode & PULLDOWN) {
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pinFunction |= FUN_PD;
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}
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pinFunction |= ((uint32_t)2 << FUN_DRV_S);//what are the drivers?
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pinFunction |= FUN_IE;//input enable but required for output as well?
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if(mode & (INPUT | OUTPUT)) {
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pinFunction |= ((uint32_t)2 << MCU_SEL_S);
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} else if(mode == SPECIAL) {
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pinFunction |= ((uint32_t)(((pin)==1||(pin)==3)?0:1) << MCU_SEL_S);
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} else {
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pinFunction |= ((uint32_t)(mode >> 5) << MCU_SEL_S);
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}
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ESP_REG(DR_REG_IO_MUX_BASE + pin_to_mux[pin]) = pinFunction;
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if(mode & OPEN_DRAIN) {
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pinControl = (1 << GPIO_PIN0_PAD_DRIVER_S);
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}
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GPIO.pin[pin].val = pinControl;
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//unlock gpio
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}
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static void digitalWrite(uint8_t pin, uint8_t val)
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{
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if(val) {
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if(pin < 32) {
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GPIO.out_w1ts = BIT(pin);
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} else if(pin < 34) {
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GPIO.out1_w1ts.val = BIT(pin - 32);
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}
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} else {
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if(pin < 32) {
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GPIO.out_w1tc = BIT(pin);
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} else if(pin < 34) {
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GPIO.out1_w1tc.val = BIT(pin - 32);
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}
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}
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}
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unsigned char twi_dcount = 18;
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static unsigned char twi_sda, twi_scl;
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static inline void SDA_LOW()
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{
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//Enable SDA (becomes output and since GPO is 0 for the pin,
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// it will pull the line low)
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if (twi_sda < 32) {
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GPIO.enable_w1ts = BIT(twi_sda);
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} else {
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GPIO.enable1_w1ts.val = BIT(twi_sda - 32);
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}
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}
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static inline void SDA_HIGH()
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{
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//Disable SDA (becomes input and since it has pullup it will go high)
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if (twi_sda < 32) {
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GPIO.enable_w1tc = BIT(twi_sda);
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} else {
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GPIO.enable1_w1tc.val = BIT(twi_sda - 32);
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}
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}
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static inline uint32_t SDA_READ()
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{
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if (twi_sda < 32) {
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return (GPIO.in & BIT(twi_sda)) != 0;
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} else {
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return (GPIO.in1.val & BIT(twi_sda - 32)) != 0;
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}
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}
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static void SCL_LOW()
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{
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if (twi_scl < 32) {
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GPIO.enable_w1ts = BIT(twi_scl);
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} else {
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GPIO.enable1_w1ts.val = BIT(twi_scl - 32);
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}
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}
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static void SCL_HIGH()
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{
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if (twi_scl < 32) {
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GPIO.enable_w1tc = BIT(twi_scl);
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} else {
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GPIO.enable1_w1tc.val = BIT(twi_scl - 32);
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}
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}
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static uint32_t SCL_READ()
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{
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if (twi_scl < 32) {
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return (GPIO.in & BIT(twi_scl)) != 0;
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} else {
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return (GPIO.in1.val & BIT(twi_scl - 32)) != 0;
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}
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}
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#ifndef FCPU80
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#define FCPU80 80000000L
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#endif
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#if F_CPU == FCPU80
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#define TWI_CLOCK_STRETCH 800
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#else
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#define TWI_CLOCK_STRETCH 1600
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#endif
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void twi_setClock(unsigned int freq)
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{
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#if F_CPU == FCPU80
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if(freq <= 100000) {
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twi_dcount = 19; //about 100KHz
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} else if(freq <= 200000) {
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twi_dcount = 8; //about 200KHz
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} else if(freq <= 300000) {
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twi_dcount = 3; //about 300KHz
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} else if(freq <= 400000) {
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twi_dcount = 1; //about 400KHz
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} else {
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twi_dcount = 1; //about 400KHz
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}
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#else
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if(freq <= 100000) {
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twi_dcount = 32; //about 100KHz
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} else if(freq <= 200000) {
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twi_dcount = 14; //about 200KHz
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} else if(freq <= 300000) {
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twi_dcount = 8; //about 300KHz
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} else if(freq <= 400000) {
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twi_dcount = 5; //about 400KHz
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} else if(freq <= 500000) {
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twi_dcount = 3; //about 500KHz
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} else if(freq <= 600000) {
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twi_dcount = 2; //about 600KHz
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} else {
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twi_dcount = 1; //about 700KHz
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}
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#endif
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}
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void twi_init(unsigned char sda, unsigned char scl)
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{
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twi_sda = sda;
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twi_scl = scl;
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pinMode(twi_sda, OUTPUT);
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pinMode(twi_scl, OUTPUT);
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digitalWrite(twi_sda, 0);
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digitalWrite(twi_scl, 0);
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pinMode(twi_sda, INPUT_PULLUP);
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pinMode(twi_scl, INPUT_PULLUP);
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twi_setClock(100000);
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}
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void twi_stop(void)
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{
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pinMode(twi_sda, INPUT);
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pinMode(twi_scl, INPUT);
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}
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static void twi_delay(unsigned char v)
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{
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unsigned int i;
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wunused-but-set-variable"
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unsigned int reg;
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for(i=0; i<v; i++) {
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reg = REG_READ(GPIO_IN_REG);
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}
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#pragma GCC diagnostic pop
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}
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static bool twi_write_start(void)
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{
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SCL_HIGH();
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SDA_HIGH();
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if (SDA_READ() == 0) {
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return false;
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}
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twi_delay(twi_dcount);
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SDA_LOW();
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twi_delay(twi_dcount);
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return true;
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}
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static bool twi_write_stop(void)
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{
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unsigned int i = 0;
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SCL_LOW();
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SDA_LOW();
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twi_delay(twi_dcount);
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SCL_HIGH();
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while (SCL_READ() == 0 && (i++) < TWI_CLOCK_STRETCH);// Clock stretching (up to 100us)
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twi_delay(twi_dcount);
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SDA_HIGH();
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twi_delay(twi_dcount);
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return true;
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}
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bool do_log = false;
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static bool twi_write_bit(bool bit)
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{
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unsigned int i = 0;
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SCL_LOW();
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if (bit) {
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SDA_HIGH();
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if (do_log) {
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twi_delay(twi_dcount+1);
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}
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} else {
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SDA_LOW();
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if (do_log) {}
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}
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twi_delay(twi_dcount+1);
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SCL_HIGH();
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while (SCL_READ() == 0 && (i++) < TWI_CLOCK_STRETCH);// Clock stretching (up to 100us)
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twi_delay(twi_dcount);
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return true;
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}
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static bool twi_read_bit(void)
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{
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unsigned int i = 0;
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SCL_LOW();
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SDA_HIGH();
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twi_delay(twi_dcount+2);
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SCL_HIGH();
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while (SCL_READ() == 0 && (i++) < TWI_CLOCK_STRETCH);// Clock stretching (up to 100us)
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bool bit = SDA_READ();
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twi_delay(twi_dcount);
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return bit;
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}
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static bool twi_write_byte(unsigned char byte)
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{
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if (byte == 0x43) {
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// printf("TWB %02x ", (uint32_t) byte);
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// do_log = true;
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}
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unsigned char bit;
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for (bit = 0; bit < 8; bit++) {
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twi_write_bit((byte & 0x80) != 0);
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byte <<= 1;
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}
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if (do_log) {
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printf("\n");
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do_log = false;
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}
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return !twi_read_bit();//NACK/ACK
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}
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static unsigned char twi_read_byte(bool nack)
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{
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unsigned char byte = 0;
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unsigned char bit;
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for (bit = 0; bit < 8; bit++) {
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byte = (byte << 1) | twi_read_bit();
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}
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twi_write_bit(nack);
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return byte;
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}
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unsigned char twi_writeTo(unsigned char address, unsigned char * buf, unsigned int len, unsigned char sendStop)
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{
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unsigned int i;
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if(!twi_write_start()) {
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return 4; //line busy
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}
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if(!twi_write_byte(((address << 1) | 0) & 0xFF)) {
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if (sendStop) {
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twi_write_stop();
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}
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return 2; //received NACK on transmit of address
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}
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for(i=0; i<len; i++) {
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if(!twi_write_byte(buf[i])) {
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if (sendStop) {
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twi_write_stop();
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}
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return 3;//received NACK on transmit of data
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}
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}
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if(sendStop) {
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twi_write_stop();
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}
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i = 0;
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while(SDA_READ() == 0 && (i++) < 10) {
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SCL_LOW();
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twi_delay(twi_dcount);
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SCL_HIGH();
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twi_delay(twi_dcount);
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}
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return 0;
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}
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unsigned char twi_readFrom(unsigned char address, unsigned char* buf, unsigned int len, unsigned char sendStop)
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{
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unsigned int i;
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if(!twi_write_start()) {
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return 4; //line busy
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}
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if(!twi_write_byte(((address << 1) | 1) & 0xFF)) {
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if (sendStop) {
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twi_write_stop();
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}
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return 2;//received NACK on transmit of address
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}
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for(i=0; i<(len-1); i++) {
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buf[i] = twi_read_byte(false);
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}
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buf[len-1] = twi_read_byte(true);
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if(sendStop) {
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twi_write_stop();
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}
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i = 0;
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while(SDA_READ() == 0 && (i++) < 10) {
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SCL_LOW();
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twi_delay(twi_dcount);
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SCL_HIGH();
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twi_delay(twi_dcount);
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}
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return 0;
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}
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