root / trunk / bootloader / rs485_poll.h @ 258
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1 | 154 | bneuman | /********
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2 | * This file is part of Tooltron.
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3 | *
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4 | * Tooltron is free software: you can redistribute it and/or modify
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5 | * it under the terms of the Lesser GNU General Public License as published by
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6 | * the Free Software Foundation, either version 3 of the License, or
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7 | * (at your option) any later version.
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8 | *
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9 | * Tooltron is distributed in the hope that it will be useful,
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10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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12 | * Lesser GNU General Public License for more details.
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13 | * You should have received a copy of the Lesser GNU General Public License
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14 | * along with Tooltron. If not, see <http://www.gnu.org/licenses/>.
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15 | *
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16 | * Copyright 2009 Kevin Woo <kwoo@2ndt.com>
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17 | *
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18 | ********/
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19 | 185 | kwoo | /**
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20 | * @file rs485_poll.h
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21 | * @brief Implements rs485 using the uart hardware module.
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22 | 154 | bneuman | *
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23 | 188 | kwoo | * This is compiled for the bootloader so this is just a header file
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24 | 154 | bneuman | *
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25 | 185 | kwoo | * @author Kevin Woo (kwoo)
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26 | 154 | bneuman | */
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27 | |||
28 | 184 | kwoo | #ifndef _RS485_SW_H
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29 | #define _RS485_SW_H
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30 | 154 | bneuman | |
31 | #include <avr/io.h> |
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32 | #include <avr/interrupt.h> |
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33 | #include <stdint.h> |
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34 | |||
35 | 184 | kwoo | #define RS485_TX_OFF 0 |
36 | #define RS485_TX_ON 1 |
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37 | |||
38 | 198 | kwoo | /**
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39 | * @brief This is the value to pass into UBRR to set the baudrate.
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40 | * @note this assumes an 8MHz system clock
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41 | */
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42 | #define BAUD9600 51 |
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43 | |||
44 | 184 | kwoo | /** @brief RX Pin for the RS485 */
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45 | 154 | bneuman | #define RX _BV(PORTD0)
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46 | 184 | kwoo | /** @brief TX Pin for the RS485 */
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47 | 154 | bneuman | #define TX _BV(PORTD1)
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48 | 184 | kwoo | /** @brief TX Enable Pin for the RS485 */
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49 | 154 | bneuman | #define TX_EN _BV(PORTD5)
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50 | |||
51 | 188 | kwoo | /**
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52 | * @brief Initializes the uart
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53 | * @param baud The baudrate. Use the definitions in rs485_sw.h
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54 | */
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55 | 185 | kwoo | void rs485_init(uint16_t baud);
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56 | 188 | kwoo | /**
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57 | * @brief Non-blocking receive
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58 | *
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59 | * Receives a byte from the UART if one exists. If none exist the function
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60 | * will return an error code immediately. If there is a byte to receive,
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61 | * it will be placed in a passed in pointer and return.
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62 | *
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63 | * @pre The RS485 TXEN line is not enabled
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64 | * @param output_byte Byte to store the received message
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65 | * @return 0 on success, negative if there is nothing to receive
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66 | */
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67 | 185 | kwoo | int8_t rs485_get_byte(uint8_t *output_byte); |
68 | 188 | kwoo | /**
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69 | * @brief Blocking send
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70 | *
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71 | * Sends the byte in data onto the network. The function will block until
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72 | * the transmit is complete so that the transmit enable line can be toggled
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73 | * safely. It will wait until any current transmission completes before sending
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74 | * and will wait until it completes before returning. The RS485 TX enable line
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75 | * is automatically toggled by the function and should not be done so
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76 | * outside the function.
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77 | *
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78 | * @param data The byte to send
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79 | */
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80 | 185 | kwoo | void rs485_send_byte(uint8_t data);
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81 | 154 | bneuman | #endif |