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Diffstat (limited to 'tmk_core/protocol/serial_soft.c')
| -rw-r--r-- | tmk_core/protocol/serial_soft.c | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/tmk_core/protocol/serial_soft.c b/tmk_core/protocol/serial_soft.c new file mode 100644 index 0000000000..44822b7e43 --- /dev/null +++ b/tmk_core/protocol/serial_soft.c @@ -0,0 +1,240 @@ +/* +Copyright 2012 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 <util/delay.h> +#include "serial.h" + +/* + * Stupid Inefficient Busy-wait Software Serial + * which is still useful for negative logic signal like Sun protocol + * if it is not supported by hardware UART. + * + * TODO: delay is not accurate enough. Instruction cycle should be counted and inline assemby is needed. + */ + +#define WAIT_US (1000000L/SERIAL_SOFT_BAUD) + +#ifdef SERIAL_SOFT_LOGIC_NEGATIVE + #define SERIAL_SOFT_RXD_IN() !(SERIAL_SOFT_RXD_READ()) + #define SERIAL_SOFT_TXD_ON() SERIAL_SOFT_TXD_LO() + #define SERIAL_SOFT_TXD_OFF() SERIAL_SOFT_TXD_HI() +#else + #define SERIAL_SOFT_RXD_IN() !!(SERIAL_SOFT_RXD_READ()) + #define SERIAL_SOFT_TXD_ON() SERIAL_SOFT_TXD_HI() + #define SERIAL_SOFT_TXD_OFF() SERIAL_SOFT_TXD_LO() +#endif + +#ifdef SERIAL_SOFT_PARITY_EVEN + #define SERIAL_SOFT_PARITY_VAL 0 +#elif defined(SERIAL_SOFT_PARITY_ODD) + #define SERIAL_SOFT_PARITY_VAL 1 +#endif + +/* debug for signal timing, see debug pin with oscilloscope */ +#define SERIAL_SOFT_DEBUG +#ifdef SERIAL_SOFT_DEBUG + #define SERIAL_SOFT_DEBUG_INIT() (DDRD |= 1<<7) + #define SERIAL_SOFT_DEBUG_TGL() (PORTD ^= 1<<7) +#else + #define SERIAL_SOFT_DEBUG_INIT() + #define SERIAL_SOFT_DEBUG_TGL() +#endif + + +void serial_init(void) +{ + SERIAL_SOFT_DEBUG_INIT(); + + SERIAL_SOFT_RXD_INIT(); + SERIAL_SOFT_TXD_INIT(); +} + +/* RX ring buffer */ +#define RBUF_SIZE 8 +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; + 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; + return data; +} + +void serial_send(uint8_t data) +{ + /* signal state: IDLE: ON, START: OFF, STOP: ON, DATA0: OFF, DATA1: ON */ + +#ifdef SERIAL_SOFT_BIT_ORDER_MSB + #ifdef SERIAL_SOFT_DATA_7BIT + uint8_t mask = 0x40; + #else + uint8_t mask = 0x80; + #endif +#else + uint8_t mask = 0x01; +#endif + + uint8_t parity = 0; + + /* start bit */ + SERIAL_SOFT_TXD_OFF(); + _delay_us(WAIT_US); + +#ifdef SERIAL_SOFT_DATA_7BIT + while (mask&0x7F) { +#else + while (mask&0xFF) { +#endif + if (data&mask) { + SERIAL_SOFT_TXD_ON(); + parity ^= 1; + } else { + SERIAL_SOFT_TXD_OFF(); + } + _delay_us(WAIT_US); + +#ifdef SERIAL_SOFT_BIT_ORDER_MSB + mask >>= 1; +#else + mask <<= 1; +#endif + } + +#if defined(SERIAL_SOFT_PARITY_EVEN) || defined(SERIAL_SOFT_PARITY_ODD) + /* to center of parity bit */ + if (parity != SERIAL_SOFT_PARITY_VAL) { + SERIAL_SOFT_TXD_ON(); + } else { + SERIAL_SOFT_TXD_OFF(); + } + _delay_us(WAIT_US); +#endif + + /* stop bit */ + SERIAL_SOFT_TXD_ON(); + _delay_us(WAIT_US); +} + +/* detect edge of start bit */ +ISR(SERIAL_SOFT_RXD_VECT) +{ + SERIAL_SOFT_DEBUG_TGL(); + SERIAL_SOFT_RXD_INT_ENTER() + + uint8_t data = 0; + +#ifdef SERIAL_SOFT_BIT_ORDER_MSB + #ifdef SERIAL_SOFT_DATA_7BIT + uint8_t mask = 0x40; + #else + uint8_t mask = 0x80; + #endif +#else + uint8_t mask = 0x01; +#endif + + uint8_t parity = 0; + + /* to center of start bit */ + _delay_us(WAIT_US/2); + SERIAL_SOFT_DEBUG_TGL(); + do { + /* to center of next bit */ + _delay_us(WAIT_US); + + SERIAL_SOFT_DEBUG_TGL(); + if (SERIAL_SOFT_RXD_IN()) { + data |= mask; + parity ^= 1; + } +#ifdef SERIAL_SOFT_BIT_ORDER_MSB + mask >>= 1; +#else + mask <<= 1; +#endif +#ifdef SERIAL_SOFT_DATA_7BIT + } while (mask&0x7F); +#else + } while (mask&0xFF); +#endif + +#if defined(SERIAL_SOFT_PARITY_EVEN) || defined(SERIAL_SOFT_PARITY_ODD) + /* to center of parity bit */ + _delay_us(WAIT_US); + if (SERIAL_SOFT_RXD_IN()) { parity ^= 1; } + SERIAL_SOFT_DEBUG_TGL(); +#endif + + /* to center of stop bit */ + _delay_us(WAIT_US); + + uint8_t next = (rbuf_head + 1) % RBUF_SIZE; +#if defined(SERIAL_SOFT_PARITY_EVEN) || defined(SERIAL_SOFT_PARITY_ODD) + if ((parity == SERIAL_SOFT_PARITY_VAL) && next != rbuf_tail) { +#else + if (next != rbuf_tail) { +#endif + rbuf[rbuf_head] = data; + rbuf_head = next; + } + + SERIAL_SOFT_RXD_INT_EXIT(); + SERIAL_SOFT_DEBUG_TGL(); +} |