git.zerfleddert.de Git - fnordlicht-mini/blob - firmware/fnordlicht-bootloader/uart.h

   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 #ifndef UART_H
  25 #define UART_H
  26
  27 #include <stdbool.h>
  28
  29
  30 /* define uart mode (8N1) */
  31 #if defined(__AVR_ATmega8__)
  32 /* in atmega8, we need a special switching bit
  33  * for addressing UCSRC */
  34 #define UART_UCSRC _BV(URSEL) | _BV(UCSZ0) | _BV(UCSZ1)
  35
  36 #elif defined(__AVR_ATmega88__) || defined(__AVR_ATmega168__)
  37 /* in atmega88, this isn't needed any more */
  38 #define UART_UCSRC _BV(_UCSZ0_UART0) | _BV(_UCSZ1_UART0)
  39 #endif
  40
  41
  42 static inline void uart_init(void)
  43 {
  44     #define BAUD CONFIG_SERIAL_BAUDRATE
  45     #include <util/setbaud.h>
  46     /* set baud rate */
  47     _UBRRH_UART0 = UBRRH_VALUE;
  48     _UBRRL_UART0 = UBRRL_VALUE;
  49
  50     #if USE_2X
  51     _UCSRA_UART0 |= (1 << _U2X_UART0);
  52     #endif
  53
  54     /* set mode */
  55     _UCSRC_UART0 = UART_UCSRC;
  56
  57     /* enable transmitter and receiver */
  58     _UCSRB_UART0 = _BV(_TXEN_UART0) | _BV(_RXEN_UART0);
  59 }
  60
  61 static inline bool uart_receive_complete(void)
  62 {
  63     return _UCSRA_UART0 & _BV(_RXC_UART0);
  64 }
  65
  66 static inline bool uart_send_complete(void)
  67 {
  68     return _BV(_UDRE_UART0) & _UCSRA_UART0;
  69 }
  70
  71 static inline uint8_t uart_getc(void)
  72 {
  73     return _UDR_UART0;
  74 }
  75
  76 static void uart_putc(uint8_t data)
  77 {
  78     while(!(_BV(_UDRE_UART0) & _UCSRA_UART0));
  79     UDR0 = data;
  80 }
  81
  82 #endif