betaflight/src/main/io/rcsplit.c

/*
 * This file is part of Cleanflight.
 *
 * Cleanflight 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.
 *
 * Cleanflight 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 Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdbool.h>
#include <stdint.h>

#include <platform.h>

#include "common/utils.h"

#include "fc/rc_controls.h"
#include "fc/rc_modes.h"
#include "fc/runtime_config.h"

#include "io/rcsplit.h"
#include "io/serial.h"


// communicate with camera device variables
STATIC_UNIT_TESTED serialPort_t *rcSplitSerialPort = NULL;
// only for unit test
STATIC_UNIT_TESTED rcsplitSwitchState_t switchStates[BOXCAMERA3 - BOXCAMERA1 + 1];

static uint8_t crc_high_first(uint8_t *ptr, uint8_t len)
{
    uint8_t crc = 0x00;
    while (len--) {
        crc ^= *ptr++;
        for (int i=8; i>0; --i) {
            if (crc & 0x80) {
                crc = (crc << 1) ^ 0x31;
            } else {
                crc = (crc << 1);
            }
        }
    }
    return crc;
}

static void sendCtrlCommand(rcsplit_ctrl_argument_e argument)
{
    uint8_t uart_buffer[5] = {0};

    uart_buffer[0] = RCSPLIT_PACKET_HEADER;
    uart_buffer[1] = RCSPLIT_PACKET_CMD_CTRL;
    uart_buffer[2] = argument;
    uart_buffer[3] = RCSPLIT_PACKET_TAIL;
    uint8_t crc = crc_high_first(uart_buffer, 4);

    // build up a full request [header]+[command]+[argument]+[crc]+[tail]
    uart_buffer[3] = crc;
    uart_buffer[4] = RCSPLIT_PACKET_TAIL;

    // write to device
    serialWriteBuf(rcSplitSerialPort, uart_buffer, 5);
}

static void rcSplitProcessMode(void)
{
    for (boxId_e i = BOXCAMERA1; i <= BOXCAMERA3; i++) {
        const uint8_t switchIndex = i - BOXCAMERA1;
        if (IS_RC_MODE_ACTIVE(i)) {
            // check last state of this mode, if it's true, then ignore it.
            // Here is a logic to make a toggle control for this mode
            if (switchStates[switchIndex].isActivated) {
                continue;
            }

            uint8_t argument = RCSPLIT_CTRL_ARGU_INVALID;
            switch (i) {
            case BOXCAMERA1:
                // check  whether arm unlock, we found a bug in rcsplit firmware:
                // if rcsplit running without Wi-Fi module, and user try to turn on wifi, it'll cause rcsplit to turn off itself, this is danger
                if (!ARMING_FLAG(ARMED)) {
                    argument = RCSPLIT_CTRL_ARGU_WIFI_BTN;
                }
                break;
            case BOXCAMERA2:
                argument = RCSPLIT_CTRL_ARGU_POWER_BTN;
                break;
            case BOXCAMERA3:
                argument = RCSPLIT_CTRL_ARGU_CHANGE_MODE;
                break;
            default:
                argument = RCSPLIT_CTRL_ARGU_INVALID;
                break;
            }

            if (argument != RCSPLIT_CTRL_ARGU_INVALID) {
                sendCtrlCommand(argument);
                switchStates[switchIndex].isActivated = true;
            }
        } else {
            switchStates[switchIndex].isActivated = false;
        }
    }
}

bool rcSplitIsEnabled(void)
{
    return rcSplitSerialPort ? true : false;
}

bool rcSplitInit(void)
{
    // found the port config with FUNCTION_RUNCAM_SPLIT_CONTROL
    // User must set some UART inteface with RunCam Split at peripherals column in Ports tab
    serialPortConfig_t *portConfig = findSerialPortConfig(FUNCTION_RCSPLIT);
    if (portConfig) {
        rcSplitSerialPort = openSerialPort(portConfig->identifier, FUNCTION_RCSPLIT, NULL, 115200, MODE_RXTX, 0);
    }

    if (!rcSplitSerialPort) {
        return false;
    }

    // set init value to true, to avoid the action auto run when the flight board start and the switch is on.
    for (boxId_e i = BOXCAMERA1; i <= BOXCAMERA3; i++) {
        uint8_t switchIndex = i - BOXCAMERA1;
        switchStates[switchIndex].isActivated = true;
    }

    return true;
}

void rcSplitUpdate(timeUs_t currentTimeUs)
{
    UNUSED(currentTimeUs);

    // process rcsplit custom mode if has any changed
    rcSplitProcessMode();
}