diff options
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 <[email protected]> + +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(); +} | 
