LibrePilot/flight/pios/inc/pios_sbus_priv.h

/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @addtogroup   PIOS_SBus S.Bus Functions
 * @brief PIOS interface to read and write from Futaba S.Bus port
 * @{
 *
 * @file       pios_sbus_priv.h
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2011.
 * @brief      Futaba S.Bus Private structures.
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#ifndef PIOS_SBUS_PRIV_H
#define PIOS_SBUS_PRIV_H

#include <pios.h>
#include <pios_stm32.h>
#include <pios_usart_priv.h>

/*
 * S.Bus serial port settings:
 *  100000bps inverted serial stream, 8 bits, even parity, 2 stop bits
 *  frame period is 7ms (HS) or 14ms (FS)
 *
 * Frame structure:
 *  1 byte  - 0x0f (start of frame byte)
 * 22 bytes - channel data (11 bit/channel, 16 channels, LSB first)
 *  1 byte  - bit flags:
 *                   0x01 - discrete channel 1,
 *                   0x02 - discrete channel 2,
 *                   0x04 - lost frame flag,
 *                   0x08 - failsafe flag,
 *                   0xf0 - reserved
 *  1 byte  - 0x00 (end of frame byte)
 *
 * The R7008SB receiver has four different end of frame bytes, which rotates in order:
 *    00000100
 *    00010100
 *    00100100
 *    00110100
 */

#define SBUS_FRAME_LENGTH             (1 + 22 + 1 + 1)
#define SBUS_SOF_BYTE                 0x0f
#define SBUS_EOF_BYTE                 0x00
#define SBUS_FLAG_DC1                 0x01
#define SBUS_FLAG_DC2                 0x02
#define SBUS_FLAG_FL                  0x04
#define SBUS_FLAG_FS                  0x08

#define SBUS_R7008SB_EOF_COUNTER_MASK 0xCF
#define SBUS_R7008SB_EOF_BYTE         0x04

/*
 * S.Bus protocol provides 16 proportional and 2 discrete channels.
 * Do not change unless driver code is updated accordingly.
 */
#if (PIOS_SBUS_NUM_INPUTS != (16 + 2))
#error "S.Bus protocol provides 16 proportional and 2 discrete channels"
#endif

/* Discrete channels represented as bits, provide values for them */
#define SBUS_VALUE_MIN 352
#define SBUS_VALUE_MAX 1696

/*
 * S.Bus configuration programmable invertor
 */
struct pios_sbus_cfg {
    struct stm32_gpio inv;
    void      (*gpio_clk_func)(uint32_t periph, FunctionalState state);
    uint32_t  gpio_clk_periph;
    BitAction gpio_inv_enable;
    BitAction gpio_inv_disable;
};

extern const struct pios_rcvr_driver pios_sbus_rcvr_driver;

extern int32_t PIOS_SBus_Init(uint32_t *sbus_id,
                              const struct pios_sbus_cfg *cfg,
                              const struct pios_com_driver *driver,
                              uint32_t lower_id);

#endif /* PIOS_SBUS_PRIV_H */

/**
 * @}
 * @}
 */