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# MightyPork's AVR Library |
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# "porklib", MightyPork's Arduino Library |
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I program my Arduinos in plain C, compile it with `avr-gcc` and flash with `avrdude` (all on Linux). |
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This library aims to make development for AVR in C easy and fun. |
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Whenever I learn how to do something, I make a library file and put it here. |
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Modules of the library provide facilities for pin numbering and aliasing, |
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bitwise operations and accessing internal and external peripherals of the AVR. |
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The code is tested and optimized for **ATmega328P**, which is used in most Arduinos. I use "Pro Mini" and "Nano". |
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It takes some inspiration from Arduino, but is written in pure C, which makes it faster |
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and smaller. |
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# How to use |
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Pull requests to add new modules are welcome, please go ahead! |
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Link the `lib/` folder to your project, and make sure you add all lib `.c` files to your `Makefile`, so it builds are the needed code. |
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Some library files don't have `.c`, but many do. |
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## Useful things |
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- To easily alias I/O pins, use `lib/pins.h`. |
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- For Arduino pins, there are presets in `lib/arduino_pins.h` |
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- Binary/byte manipulation utilities are in `lib/calc.h` |
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- `lib/meta.h` contains some generally useful things that didn't fit elsewhere |
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Each header file contains a comment block with explanation, which will help you understand them. |
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## License |
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The library is provided under MIT license, see the LICENSE file for more info. |
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@ -0,0 +1,224 @@ |
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#include <avr/io.h> |
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#include <util/delay.h> |
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#include <stdint.h> |
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#include <stdbool.h> |
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#include "iopins.h" |
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#include "onewire.h" |
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/** Perform bus reset. Returns true if any device is connected */ |
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bool ow_reset(const uint8_t pin) |
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{ |
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as_output_n(pin); |
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pin_low_n(pin); |
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_delay_us(480); |
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as_input_pu_n(pin); |
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_delay_us(70); |
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const bool a = get_pin_n(pin); |
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_delay_us(410); |
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return a; |
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} |
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/** Send a single bit */ |
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void ow_tx_bit(const uint8_t pin, const bool bit) |
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{ |
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as_output_n(pin); |
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pin_low_n(pin); |
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if (bit) { |
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_delay_us(6); |
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as_input_pu_n(pin); |
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_delay_us(64); |
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} else { |
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_delay_us(60); |
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as_input_pu_n(pin); |
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_delay_us(10); |
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} |
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} |
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/** Send a single byte */ |
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void ow_send(const uint8_t pin, const uint8_t byte) |
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{ |
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for (uint8_t i = 0; i < 8; i++) |
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{ |
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ow_tx_bit(pin, (byte >> i) & 0x01); |
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} |
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} |
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/** Read a single bit */ |
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bool ow_rx_bit(const uint8_t pin) |
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{ |
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as_output_n(pin); |
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pin_low_n(pin); |
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_delay_us(6); |
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as_input_pu_n(pin); |
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_delay_us(9); |
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const bool a = get_pin_n(pin); |
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_delay_us(55); |
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return a; |
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} |
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/** Read a single byte */ |
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uint8_t ow_read(const uint8_t pin) |
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{ |
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uint8_t byte = 0; |
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for (uint8_t i = 0; i < 8; i++) |
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{ |
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byte = (byte >> 1) | (ow_rx_bit(pin) << 7); |
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} |
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return byte; |
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} |
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/** Wait until the device is ready. Returns false on timeout */ |
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bool ow_wait_ready(const uint8_t pin) |
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{ |
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uint16_t timeout = 700; |
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as_input_pu_n(pin); |
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while (--timeout > 0) |
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{ |
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if (is_high_n(pin)) return true; |
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_delay_ms(1); |
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} |
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return false; |
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} |
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/** Read bytes into an array */ |
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void ow_read_arr(const uint8_t pin, uint8_t* array, const uint8_t count) |
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{ |
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for (uint8_t i = 0; i < count; i++) |
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{ |
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array[i] = ow_read(pin); |
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} |
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} |
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// ---------- CRC utils ----------
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/*
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Dallas 1-wire CRC routines for Arduino with examples of usage. |
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The 16-bit routine is new. |
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The 8-bit routine is from http://github.com/paeaetech/paeae/tree/master/Libraries/ds2482/
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Copyright (C) 2010 Kairama Inc |
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This program is free software: you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation, either version 3 of the License, or |
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(at your option) any later version. |
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This program 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 |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/ |
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// Dallas 1-wire 16-bit CRC calculation. Developed from Maxim Application Note 27.
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/** Compute a CRC16 checksum */ |
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uint16_t crc16( uint8_t *data, uint8_t len) |
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{ |
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uint16_t crc = 0; |
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for (uint8_t i = 0; i < len; i++) |
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{ |
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uint8_t inbyte = data[i]; |
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for (uint8_t j = 0; j < 8; j++) |
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{ |
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uint8_t mix = (crc ^ inbyte) & 0x01; |
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crc = crc >> 1; |
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if (mix) |
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crc = crc ^ 0xA001; |
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inbyte = inbyte >> 1; |
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} |
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} |
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return crc; |
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} |
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// The 1-Wire CRC scheme is described in Maxim Application Note 27:
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// "Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products"
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/** Compute a CRC8 checksum */ |
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uint8_t crc8(uint8_t *addr, uint8_t len) |
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{ |
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uint8_t crc = 0; |
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for (uint8_t i = 0; i < len; i++) |
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{ |
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uint8_t inbyte = addr[i]; |
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for (uint8_t j = 0; j < 8; j++) |
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{ |
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uint8_t mix = (crc ^ inbyte) & 0x01; |
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crc >>= 1; |
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if (mix) |
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crc ^= 0x8C; |
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inbyte >>= 1; |
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} |
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} |
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return crc; |
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} |
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// --- utils for DS1820 ---
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/** Read temperature in 0.0625°C, or TEMP_ERROR on error */ |
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int16_t ds1820_read_temp(uint8_t pin) |
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{ |
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ow_send(pin, READ_SCRATCHPAD); |
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uint8_t bytes[9]; |
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ow_read_arr(pin, bytes, 9); |
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uint8_t crc = crc8(bytes, 8); |
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if (crc != bytes[8]) { |
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return TEMP_ERROR; |
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} else { |
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int16_t a = ((bytes[1] << 8) | bytes[0]) >> 1; |
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a = a << 4; |
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a += (16 - bytes[6]) & 0x0F; |
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a -= 0x04; |
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return a; |
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} |
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} |
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/** Read temperature in 0.1°C, or TEMP_ERROR on error */ |
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int16_t ds1820_read_temp_c(uint8_t pin) |
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{ |
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int32_t temp = ds1820_read_temp(pin); |
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if (temp == TEMP_ERROR) |
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return TEMP_ERROR; |
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temp *= 625; |
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uint16_t rem = temp % 1000; |
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temp /= 1000; |
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if (rem >= 500) temp++; |
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return (int16_t) temp; |
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} |
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