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- /*
- Copyright 2012 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 <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 */
- #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();
- }
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