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Diffstat (limited to 'keyboards/hhkb/serial_uart.c')
-rw-r--r-- | keyboards/hhkb/serial_uart.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/keyboards/hhkb/serial_uart.c b/keyboards/hhkb/serial_uart.c new file mode 100644 index 0000000000..d5b5657095 --- /dev/null +++ b/keyboards/hhkb/serial_uart.c @@ -0,0 +1,133 @@ +/* +Copyright 2013 Jun WAKO <wakojun@gmail.com> + +This software is licensed with a Modified BSD License. +All of this is supposed to be Free Software, Open Source, DFSG-free, +GPL-compatible, and OK to use in both free and proprietary applications. +Additions and corrections to this file are welcome. + + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + +* Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + +* Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in + the documentation and/or other materials provided with the + distribution. + +* Neither the name of the copyright holders nor the names of + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +POSSIBILITY OF SUCH DAMAGE. +*/ + +#include <stdbool.h> +#include <avr/io.h> +#include <avr/interrupt.h> +#include "serial.h" + +#ifndef SERIAL_UART_BAUD +# define SERIAL_UART_BAUD 9600 +#endif + +#define SERIAL_UART_UBRR (F_CPU / (16UL * SERIAL_UART_BAUD) - 1) +#define SERIAL_UART_TXD_READY (UCSR1A & _BV(UDRE1)) +#define SERIAL_UART_RXD_VECT USART1_RX_vect + +#ifndef SERIAL_UART_INIT_CUSTOM +# define SERIAL_UART_INIT_CUSTOM \ + /* enable TX */ \ + UCSR1B = _BV(TXEN1); \ + /* 8-bit data */ \ + UCSR1C = _BV(UCSZ11) | _BV(UCSZ10); +#endif + +#if defined(SERIAL_UART_RTS_LO) && defined(SERIAL_UART_RTS_HI) +// Buffer state +// Empty: RBUF_SPACE == RBUF_SIZE(head==tail) +// Last 1 space: RBUF_SPACE == 2 +// Full: RBUF_SPACE == 1(last cell of rbuf be never used.) +# define RBUF_SPACE() (rbuf_head < rbuf_tail ? (rbuf_tail - rbuf_head) : (RBUF_SIZE - rbuf_head + rbuf_tail)) +// allow to send +# define rbuf_check_rts_lo() \ + do { \ + if (RBUF_SPACE() > 2) SERIAL_UART_RTS_LO(); \ + } while (0) +// prohibit to send +# define rbuf_check_rts_hi() \ + do { \ + if (RBUF_SPACE() <= 2) SERIAL_UART_RTS_HI(); \ + } while (0) +#else +# define rbuf_check_rts_lo() +# define rbuf_check_rts_hi() +#endif + +void serial_init(void) { + do { + // Set baud rate + UBRR1L = SERIAL_UART_UBRR; + UBRR1L = SERIAL_UART_UBRR >> 8; + SERIAL_UART_INIT_CUSTOM; + } while (0); +} + +// RX ring buffer +#define RBUF_SIZE 256 +static uint8_t rbuf[RBUF_SIZE]; +static uint8_t rbuf_head = 0; +static uint8_t rbuf_tail = 0; + +uint8_t serial_recv(void) { + uint8_t data = 0; + if (rbuf_head == rbuf_tail) { + return 0; + } + + data = rbuf[rbuf_tail]; + rbuf_tail = (rbuf_tail + 1) % RBUF_SIZE; + rbuf_check_rts_lo(); + return data; +} + +int16_t serial_recv2(void) { + uint8_t data = 0; + if (rbuf_head == rbuf_tail) { + return -1; + } + + data = rbuf[rbuf_tail]; + rbuf_tail = (rbuf_tail + 1) % RBUF_SIZE; + rbuf_check_rts_lo(); + return data; +} + +void serial_send(uint8_t data) { + while (!SERIAL_UART_TXD_READY) + ; + SERIAL_UART_DATA = data; +} + +// USART RX complete interrupt +ISR(SERIAL_UART_RXD_VECT) { + uint8_t next = (rbuf_head + 1) % RBUF_SIZE; + if (next != rbuf_tail) { + rbuf[rbuf_head] = SERIAL_UART_DATA; + rbuf_head = next; + } + rbuf_check_rts_hi(); +} |