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fix config.mk file header comment
[fnordlicht-mini] / firmware / fnordlicht-firmware / uart.c
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1/* vim:ts=4 sts=4 et tw=80
2 *
3 * fnordlicht firmware
4 *
5 * for additional information please
6 * see http://lochraster.org/fnordlichtmini
7 *
8 * (c) by Alexander Neumann <alexander@bumpern.de>
9 * Lars Noschinski <lars@public.noschinski.de>
10 *
11 * This program is free software: you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License version 3 as published by
13 * the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful, but WITHOUT
16 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
17 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
18 * more details.
19 *
20 * You should have received a copy of the GNU General Public License along with
21 * this program. If not, see <http://www.gnu.org/licenses/>.
22 */
23
24#include "globals.h"
25
26#if CONFIG_SERIAL
27
28#include "../common/io.h"
29#include <avr/interrupt.h>
30
31#include "globals.h"
32#include "../common/common.h"
33#include "pwm.h"
34#include "fifo.h"
35#include "uart.h"
36
37/* define uart mode (8N1) */
38#if defined(__AVR_ATmega8__)
39/* in atmega8, we need a special switching bit
40 * for addressing UCSRC */
41#define UART_UCSRC _BV(URSEL) | _BV(UCSZ0) | _BV(UCSZ1)
42
43#elif defined(__AVR_ATmega88__) || defined(__AVR_ATmega168__)
44/* in atmega88, this isn't needed any more */
45#define UART_UCSRC _BV(_UCSZ0_UART0) | _BV(_UCSZ1_UART0)
46#endif
47
48/* global variables */
49volatile struct global_uart_t global_uart;
50
51/** output one character */
52void uart_putc(uint8_t data)
53{
54#if UART_TX_ENABLED
55 /* store data */
56 fifo_enqueue((fifo_t *)&global_uart.tx, data);
57
58 /* enable interrupt */
59 _UCSRB_UART0 |= _BV(_UDRIE_UART0);
60#endif
61}
62
63/** init the hardware uart */
64void uart_init(void)
65{
66 #define BAUD CONFIG_SERIAL_BAUDRATE
67 #include <util/setbaud.h>
68
69 /* set baud rate */
70 _UBRRH_UART0 = UBRRH_VALUE;
71 _UBRRL_UART0 = UBRRL_VALUE;
72
73 #if USE_2X
74 _UCSRA_UART0 |= (1 << _U2X_UART0);
75 #endif
76
77 /* set mode */
78 _UCSRC_UART0 = UART_UCSRC;
79
80#if UART_TX_ENABLED
81 /* enable transmitter, receiver and receiver complete interrupt */
82 _UCSRB_UART0 = _BV(_TXEN_UART0) | _BV(_RXEN_UART0) | _BV(_RXCIE_UART0);
83 /* init tx fifo */
84 fifo_init((fifo_t *)&global_uart.tx);
85#else
86 /* enable receiver and receiver complete interrupt */
87 _UCSRB_UART0 = _BV(_RXEN_UART0) | _BV(_RXCIE_UART0);
88#endif
89
90 /* init rx fifo */
91 fifo_init((fifo_t *)&global_uart.rx);
92}
93
94
95/** interrupts*/
96
97/** uart receive interrupt */
98ISR(_SIG_UART_RECV_UART0)
99{
100
101 /* store received data */
102 fifo_enqueue((fifo_t *)&global_uart.rx, _UDR_UART0);
103
104}
105
106#if UART_TX_ENABLED
107/** uart data register empty interrupt */
108ISR(_SIG_UART_DATA_UART0)
109{
110 /* load next byte to transfer */
111 _UDR_UART0 = fifo_dequeue((fifo_t *)&global_uart.tx);
112
113 /* check if this interrupt is still needed */
114 if ( fifo_fill((fifo_t *)&global_uart.tx) == 0) {
115 /* disable this interrupt */
116 _UCSRB_UART0 &= ~_BV(_UDRIE_UART0);
117 }
118}
119#endif
120
121
122#endif
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