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