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author | Lorenz Meier <lm@inf.ethz.ch> | 2013-08-17 20:30:52 +0200 |
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committer | Lorenz Meier <lm@inf.ethz.ch> | 2013-08-17 20:30:52 +0200 |
commit | 061be7f7fed430d1c235809f1e1dce61e8b7aa01 (patch) | |
tree | 5964318a7902c4eeaa67f185698e6cafc25fbf08 | |
parent | 628e806df5b05ea8a44d46f29606db03fee1fce9 (diff) | |
parent | b08ca02410cc02f75bbfe154963edcea6767972e (diff) | |
download | px4-firmware-061be7f7fed430d1c235809f1e1dce61e8b7aa01.tar.gz px4-firmware-061be7f7fed430d1c235809f1e1dce61e8b7aa01.tar.bz2 px4-firmware-061be7f7fed430d1c235809f1e1dce61e8b7aa01.zip |
Merged master
-rw-r--r-- | nuttx-configs/px4fmu-v1/nsh/defconfig | 2 | ||||
-rw-r--r-- | src/drivers/px4io/px4io.cpp | 143 | ||||
-rw-r--r-- | src/modules/px4iofirmware/dsm.c | 408 | ||||
-rw-r--r-- | src/modules/px4iofirmware/px4io.h | 2 |
4 files changed, 330 insertions, 225 deletions
diff --git a/nuttx-configs/px4fmu-v1/nsh/defconfig b/nuttx-configs/px4fmu-v1/nsh/defconfig index a7a6725c6..861d59b4b 100644 --- a/nuttx-configs/px4fmu-v1/nsh/defconfig +++ b/nuttx-configs/px4fmu-v1/nsh/defconfig @@ -268,7 +268,7 @@ CONFIG_USART2_RXDMA=y # CONFIG_USART3_RXDMA is not set # CONFIG_UART4_RXDMA is not set # CONFIG_UART5_RS485 is not set -CONFIG_UART5_RXDMA=y +CONFIG_UART5_RXDMA=n # CONFIG_USART6_RS485 is not set CONFIG_USART6_RXDMA=y # CONFIG_USART7_RXDMA is not set diff --git a/src/drivers/px4io/px4io.cpp b/src/drivers/px4io/px4io.cpp index ed98ff0a5..cebe33996 100644 --- a/src/drivers/px4io/px4io.cpp +++ b/src/drivers/px4io/px4io.cpp @@ -92,21 +92,62 @@ extern device::Device *PX4IO_serial_interface() weak_function; #define PX4IO_SET_DEBUG _IOC(0xff00, 0) #define PX4IO_INAIR_RESTART_ENABLE _IOC(0xff00, 1) +/** + * The PX4IO class. + * + * Encapsulates PX4FMU to PX4IO communications modeled as file operations. + */ class PX4IO : public device::CDev { public: + /** + * Constructor. + * + * Initialize all class variables. + */ PX4IO(device::Device *interface); + + /** + * Destructor. + * + * Wait for worker thread to terminate. + */ virtual ~PX4IO(); + /** + * Initialize the PX4IO class. + * + * Initialize the physical I2C interface to PX4IO. Retrieve relevant initial system parameters. Initialize PX4IO registers. + */ virtual int init(); + /** + * IO Control handler. + * + * Handle all IOCTL calls to the PX4IO file descriptor. + * + * @param[in] filp file handle (not used). This function is always called directly through object reference + * @param[in] cmd the IOCTL command + * @param[in] the IOCTL command parameter (optional) + */ virtual int ioctl(file *filp, int cmd, unsigned long arg); + + /** + * write handler. + * + * Handle writes to the PX4IO file descriptor. + * + * @param[in] filp file handle (not used). This function is always called directly through object reference + * @param[in] buffer pointer to the data buffer to be written + * @param[in] len size in bytes to be written + * @return number of bytes written + */ virtual ssize_t write(file *filp, const char *buffer, size_t len); /** * Set the update rate for actuator outputs from FMU to IO. * - * @param rate The rate in Hz actuator outpus are sent to IO. + * @param[in] rate The rate in Hz actuator outpus are sent to IO. * Min 10 Hz, max 400 Hz */ int set_update_rate(int rate); @@ -114,29 +155,41 @@ public: /** * Set the battery current scaling and bias * - * @param amp_per_volt - * @param amp_bias + * @param[in] amp_per_volt + * @param[in] amp_bias */ void set_battery_current_scaling(float amp_per_volt, float amp_bias); /** * Push failsafe values to IO. * - * @param vals Failsafe control inputs: in us PPM (900 for zero, 1500 for centered, 2100 for full) - * @param len Number of channels, could up to 8 + * @param[in] vals Failsafe control inputs: in us PPM (900 for zero, 1500 for centered, 2100 for full) + * @param[in] len Number of channels, could up to 8 */ int set_failsafe_values(const uint16_t *vals, unsigned len); /** - * Print the current status of IO + * Print IO status. + * + * Print all relevant IO status information */ void print_status(); + /** + * Set the DSM VCC is controlled by relay one flag + * + * @param[in] enable true=DSM satellite VCC is controlled by relay1, false=DSM satellite VCC not controlled + */ inline void set_dsm_vcc_ctl(bool enable) { _dsm_vcc_ctl = enable; }; + /** + * Get the DSM VCC is controlled by relay one flag + * + * @return true=DSM satellite VCC is controlled by relay1, false=DSM satellite VCC not controlled + */ inline bool get_dsm_vcc_ctl() { return _dsm_vcc_ctl; @@ -146,59 +199,49 @@ private: device::Device *_interface; // XXX - unsigned _hardware; - unsigned _max_actuators; - unsigned _max_controls; - unsigned _max_rc_input; - unsigned _max_relays; - unsigned _max_transfer; + unsigned _hardware; ///< Hardware revision + unsigned _max_actuators; ///<Maximum # of actuators supported by PX4IO + unsigned _max_controls; ///<Maximum # of controls supported by PX4IO + unsigned _max_rc_input; ///<Maximum receiver channels supported by PX4IO + unsigned _max_relays; ///<Maximum relays supported by PX4IO + unsigned _max_transfer; ///<Maximum number of I2C transfers supported by PX4IO - unsigned _update_interval; ///< subscription interval limiting send rate + unsigned _update_interval; ///<Subscription interval limiting send rate - volatile int _task; ///< worker task - volatile bool _task_should_exit; + volatile int _task; ///<worker task id + volatile bool _task_should_exit; ///<worker terminate flag - int _mavlink_fd; + int _mavlink_fd; ///<mavlink file descriptor - perf_counter_t _perf_update; + perf_counter_t _perf_update; ///<local performance counter /* cached IO state */ - uint16_t _status; - uint16_t _alarms; + uint16_t _status; ///<Various IO status flags + uint16_t _alarms; ///<Various IO alarms /* subscribed topics */ - int _t_actuators; ///< actuator controls topic - int _t_armed; ///< system armed control topic - int _t_vstatus; ///< system / vehicle status - int _t_param; ///< parameter update topic + int _t_actuators; ///<actuator controls topic + int _t_armed; ///<system armed control topic + int _t_vstatus; ///<system / vehicle status + int _t_param; ///<parameter update topic /* advertised topics */ - orb_advert_t _to_input_rc; ///< rc inputs from io - orb_advert_t _to_actuators_effective; ///< effective actuator controls topic - orb_advert_t _to_outputs; ///< mixed servo outputs topic - orb_advert_t _to_battery; ///< battery status / voltage - - actuator_outputs_s _outputs; ///< mixed outputs - actuator_controls_effective_s _controls_effective; ///< effective controls + orb_advert_t _to_input_rc; ///<rc inputs from IO topic + orb_advert_t _to_actuators_effective; ///<effective actuator controls topic + orb_advert_t _to_outputs; ///<mixed servo outputs topic + orb_advert_t _to_battery; ///<battery status / voltage topic - bool _primary_pwm_device; ///< true if we are the default PWM output + actuator_outputs_s _outputs; ///<mixed outputs + actuator_controls_effective_s _controls_effective; ///<effective controls - float _battery_amp_per_volt; - float _battery_amp_bias; - float _battery_mamphour_total; - uint64_t _battery_last_timestamp; + bool _primary_pwm_device; ///<true if we are the default PWM output - /** - * Relay1 is dedicated to controlling DSM receiver power - */ - - bool _dsm_vcc_ctl; - - /** - * System armed - */ + float _battery_amp_per_volt; ///<current sensor amps/volt + float _battery_amp_bias; ///<current sensor bias + float _battery_mamphour_total;///<amp hours consumed so far + uint64_t _battery_last_timestamp;///<last amp hour calculation timestamp - bool _system_armed; + bool _dsm_vcc_ctl; ///<true if relay 1 controls DSM satellite RX power /** * Trampoline to the worker task @@ -369,8 +412,7 @@ PX4IO::PX4IO(device::Device *interface) : _battery_amp_bias(0), _battery_mamphour_total(0), _battery_last_timestamp(0), - _dsm_vcc_ctl(false), - _system_armed(false) + _dsm_vcc_ctl(false) { /* we need this potentially before it could be set in task_main */ g_dev = this; @@ -705,7 +747,7 @@ PX4IO::task_main() // See if bind parameter has been set, and reset it to 0 param_get(dsm_bind_param = param_find("RC_DSM_BIND"), &dsm_bind_val); if (dsm_bind_val) { - if (!_system_armed) { + if (!(_status & PX4IO_P_STATUS_FLAGS_ARMED)) { if ((dsm_bind_val == 1) || (dsm_bind_val == 2)) { mavlink_log_info(mavlink_fd, "[IO] binding dsm%c rx", dsm_bind_val == 1 ? '2' : 'x'); ioctl(nullptr, DSM_BIND_START, dsm_bind_val == 1 ? 3 : 7); @@ -784,8 +826,6 @@ PX4IO::io_set_arming_state() uint16_t set = 0; uint16_t clear = 0; - _system_armed = vstatus.flag_system_armed; - if (armed.armed && !armed.lockdown) { set |= PX4IO_P_SETUP_ARMING_FMU_ARMED; } else { @@ -1635,7 +1675,8 @@ PX4IO::ioctl(file * /*filep*/, int cmd, unsigned long arg) } ssize_t -PX4IO::write(file *filp, const char *buffer, size_t len) +PX4IO::write(file * /*filp*/, const char *buffer, size_t len) +/* Make it obvious that file * isn't used here */ { unsigned count = len / 2; diff --git a/src/modules/px4iofirmware/dsm.c b/src/modules/px4iofirmware/dsm.c index 4925ced54..206e27db5 100644 --- a/src/modules/px4iofirmware/dsm.c +++ b/src/modules/px4iofirmware/dsm.c @@ -48,161 +48,44 @@ #include <drivers/drv_hrt.h> -#define DEBUG - #include "px4io.h" -#define DSM_FRAME_SIZE 16 -#define DSM_FRAME_CHANNELS 7 - -static int dsm_fd = -1; - -static hrt_abstime last_rx_time; -static hrt_abstime last_frame_time; - -static uint8_t frame[DSM_FRAME_SIZE]; - -static unsigned partial_frame_count; -static unsigned channel_shift; - -unsigned dsm_frame_drops; - -static bool dsm_decode_channel(uint16_t raw, unsigned shift, unsigned *channel, unsigned *value); -static void dsm_guess_format(bool reset); -static bool dsm_decode(hrt_abstime now, uint16_t *values, uint16_t *num_values); - -int -dsm_init(const char *device) -{ - if (dsm_fd < 0) - dsm_fd = open(device, O_RDONLY | O_NONBLOCK); - - if (dsm_fd >= 0) { - struct termios t; - - /* 115200bps, no parity, one stop bit */ - tcgetattr(dsm_fd, &t); - cfsetspeed(&t, 115200); - t.c_cflag &= ~(CSTOPB | PARENB); - tcsetattr(dsm_fd, TCSANOW, &t); - - /* initialise the decoder */ - partial_frame_count = 0; - last_rx_time = hrt_absolute_time(); - - /* reset the format detector */ - dsm_guess_format(true); - - debug("DSM: ready"); - - } else { - debug("DSM: open failed"); - } - - return dsm_fd; -} - -void -dsm_bind(uint16_t cmd, int pulses) -{ - const uint32_t usart1RxAsOutp = GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|GPIO_OUTPUT_SET|GPIO_PORTA|GPIO_PIN10; - - if (dsm_fd < 0) - return; - -#ifdef CONFIG_ARCH_BOARD_PX4IO_V2 - // XXX implement - #warning DSM BIND NOT IMPLEMENTED ON PX4IO V2 -#else - switch (cmd) { - case dsm_bind_power_down: - // power down DSM satellite - POWER_RELAY1(0); - break; - case dsm_bind_power_up: - POWER_RELAY1(1); - dsm_guess_format(true); - break; - case dsm_bind_set_rx_out: - stm32_configgpio(usart1RxAsOutp); - break; - case dsm_bind_send_pulses: - for (int i = 0; i < pulses; i++) { - stm32_gpiowrite(usart1RxAsOutp, false); - up_udelay(25); - stm32_gpiowrite(usart1RxAsOutp, true); - up_udelay(25); - } - break; - case dsm_bind_reinit_uart: - // Restore USART rx pin - stm32_configgpio(GPIO_USART1_RX); - break; - } -#endif -} - -bool -dsm_input(uint16_t *values, uint16_t *num_values) -{ - ssize_t ret; - hrt_abstime now; - - /* - * The DSM* protocol doesn't provide any explicit framing, - * so we detect frame boundaries by the inter-frame delay. - * - * The minimum frame spacing is 11ms; with 16 bytes at 115200bps - * frame transmission time is ~1.4ms. - * - * We expect to only be called when bytes arrive for processing, - * and if an interval of more than 5ms passes between calls, - * the first byte we read will be the first byte of a frame. - * - * In the case where byte(s) are dropped from a frame, this also - * provides a degree of protection. Of course, it would be better - * if we didn't drop bytes... - */ - now = hrt_absolute_time(); - - if ((now - last_rx_time) > 5000) { - if (partial_frame_count > 0) { - dsm_frame_drops++; - partial_frame_count = 0; - } - } +#define DSM_FRAME_SIZE 16 /**<DSM frame size in bytes*/ +#define DSM_FRAME_CHANNELS 7 /**<Max supported DSM channels*/ - /* - * Fetch bytes, but no more than we would need to complete - * the current frame. - */ - ret = read(dsm_fd, &frame[partial_frame_count], DSM_FRAME_SIZE - partial_frame_count); - - /* if the read failed for any reason, just give up here */ - if (ret < 1) - return false; - - last_rx_time = now; - - /* - * Add bytes to the current frame - */ - partial_frame_count += ret; - - /* - * If we don't have a full frame, return - */ - if (partial_frame_count < DSM_FRAME_SIZE) - return false; - - /* - * Great, it looks like we might have a frame. Go ahead and - * decode it. - */ - partial_frame_count = 0; - return dsm_decode(now, values, num_values); -} +static int dsm_fd = -1; /**< File handle to the DSM UART */ +static hrt_abstime dsm_last_rx_time; /**< Timestamp when we last received */ +static hrt_abstime dsm_last_frame_time; /**< Timestamp for start of last dsm frame */ +static uint8_t dsm_frame[DSM_FRAME_SIZE]; /**< DSM dsm frame receive buffer */ +static unsigned dsm_partial_frame_count; /**< Count of bytes received for current dsm frame */ +static unsigned dsm_channel_shift; /**< Channel resolution, 0=unknown, 1=10 bit, 2=11 bit */ +static unsigned dsm_frame_drops; /**< Count of incomplete DSM frames */ +/** + * Attempt to decode a single channel raw channel datum + * + * The DSM* protocol doesn't provide any explicit framing, + * so we detect dsm frame boundaries by the inter-dsm frame delay. + * + * The minimum dsm frame spacing is 11ms; with 16 bytes at 115200bps + * dsm frame transmission time is ~1.4ms. + * + * We expect to only be called when bytes arrive for processing, + * and if an interval of more than 5ms passes between calls, + * the first byte we read will be the first byte of a dsm frame. + * + * In the case where byte(s) are dropped from a dsm frame, this also + * provides a degree of protection. Of course, it would be better + * if we didn't drop bytes... + * + * Upon receiving a full dsm frame we attempt to decode it + * + * @param[in] raw 16 bit raw channel value from dsm frame + * @param[in] shift position of channel number in raw data + * @param[out] channel pointer to returned channel number + * @param[out] value pointer to returned channel value + * @return true=raw value successfully decoded + */ static bool dsm_decode_channel(uint16_t raw, unsigned shift, unsigned *channel, unsigned *value) { @@ -220,6 +103,11 @@ dsm_decode_channel(uint16_t raw, unsigned shift, unsigned *channel, unsigned *va return true; } +/** + * Attempt to guess if receiving 10 or 11 bit channel values + * + * @param[in] reset true=reset the 10/11 bit state to unknown + */ static void dsm_guess_format(bool reset) { @@ -232,14 +120,14 @@ dsm_guess_format(bool reset) cs10 = 0; cs11 = 0; samples = 0; - channel_shift = 0; + dsm_channel_shift = 0; return; } - /* scan the channels in the current frame in both 10- and 11-bit mode */ + /* scan the channels in the current dsm_frame in both 10- and 11-bit mode */ for (unsigned i = 0; i < DSM_FRAME_CHANNELS; i++) { - uint8_t *dp = &frame[2 + (2 * i)]; + uint8_t *dp = &dsm_frame[2 + (2 * i)]; uint16_t raw = (dp[0] << 8) | dp[1]; unsigned channel, value; @@ -250,10 +138,10 @@ dsm_guess_format(bool reset) if (dsm_decode_channel(raw, 11, &channel, &value) && (channel < 31)) cs11 |= (1 << channel); - /* XXX if we cared, we could look for the phase bit here to decide 1 vs. 2-frame format */ + /* XXX if we cared, we could look for the phase bit here to decide 1 vs. 2-dsm_frame format */ } - /* wait until we have seen plenty of frames - 2 should normally be enough */ + /* wait until we have seen plenty of frames - 5 should normally be enough */ if (samples++ < 5) return; @@ -289,13 +177,13 @@ dsm_guess_format(bool reset) } if ((votes11 == 1) && (votes10 == 0)) { - channel_shift = 11; + dsm_channel_shift = 11; debug("DSM: 11-bit format"); return; } if ((votes10 == 1) && (votes11 == 0)) { - channel_shift = 10; + dsm_channel_shift = 10; debug("DSM: 10-bit format"); return; } @@ -305,27 +193,136 @@ dsm_guess_format(bool reset) dsm_guess_format(true); } +/** + * Initialize the DSM receive functionality + * + * Open the UART for receiving DSM frames and configure it appropriately + * + * @param[in] device Device name of DSM UART + */ +int +dsm_init(const char *device) +{ + if (dsm_fd < 0) + dsm_fd = open(device, O_RDONLY | O_NONBLOCK); + + if (dsm_fd >= 0) { + + struct termios t; + + /* 115200bps, no parity, one stop bit */ + tcgetattr(dsm_fd, &t); + cfsetspeed(&t, 115200); + t.c_cflag &= ~(CSTOPB | PARENB); + tcsetattr(dsm_fd, TCSANOW, &t); + + /* initialise the decoder */ + dsm_partial_frame_count = 0; + dsm_last_rx_time = hrt_absolute_time(); + + /* reset the format detector */ + dsm_guess_format(true); + + debug("DSM: ready"); + + } else { + + debug("DSM: open failed"); + + } + + return dsm_fd; +} + +/** + * Handle DSM satellite receiver bind mode handler + * + * @param[in] cmd commands - dsm_bind_power_down, dsm_bind_power_up, dsm_bind_set_rx_out, dsm_bind_send_pulses, dsm_bind_reinit_uart + * @param[in] pulses Number of pulses for dsm_bind_send_pulses command + */ +void +dsm_bind(uint16_t cmd, int pulses) +{ + const uint32_t usart1RxAsOutp = + GPIO_OUTPUT | GPIO_CNF_OUTPP | GPIO_MODE_50MHz | GPIO_OUTPUT_SET | GPIO_PORTA | GPIO_PIN10; + + if (dsm_fd < 0) + return; + +#ifdef CONFIG_ARCH_BOARD_PX4IO_V2 + // XXX implement + #warning DSM BIND NOT IMPLEMENTED ON PX4IO V2 +#else + switch (cmd) { + + case dsm_bind_power_down: + + /*power down DSM satellite*/ + POWER_RELAY1(0); + break; + + case dsm_bind_power_up: + + /*power up DSM satellite*/ + POWER_RELAY1(1); + dsm_guess_format(true); + break; + + case dsm_bind_set_rx_out: + + /*Set UART RX pin to active output mode*/ + stm32_configgpio(usart1RxAsOutp); + break; + + case dsm_bind_send_pulses: + + /*Pulse RX pin a number of times*/ + for (int i = 0; i < pulses; i++) { + stm32_gpiowrite(usart1RxAsOutp, false); + up_udelay(25); + stm32_gpiowrite(usart1RxAsOutp, true); + up_udelay(25); + } + break; + + case dsm_bind_reinit_uart: + + /*Restore USART RX pin to RS232 receive mode*/ + stm32_configgpio(GPIO_USART1_RX); + break; + + } +#endif +} + +/** + * Decode the entire dsm frame (all contained channels) + * + * @param[in] frame_time timestamp when this dsm frame was received. Used to detect RX loss in order to reset 10/11 bit guess. + * @param[out] values pointer to per channel array of decoded values + * @param[out] num_values pointer to number of raw channel values returned + * @return true=DSM frame successfully decoded, false=no update + */ static bool dsm_decode(hrt_abstime frame_time, uint16_t *values, uint16_t *num_values) { - /* - debug("DSM frame %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x", - frame[0], frame[1], frame[2], frame[3], frame[4], frame[5], frame[6], frame[7], - frame[8], frame[9], frame[10], frame[11], frame[12], frame[13], frame[14], frame[15]); + debug("DSM dsm_frame %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x", + dsm_frame[0], dsm_frame[1], dsm_frame[2], dsm_frame[3], dsm_frame[4], dsm_frame[5], dsm_frame[6], dsm_frame[7], + dsm_frame[8], dsm_frame[9], dsm_frame[10], dsm_frame[11], dsm_frame[12], dsm_frame[13], dsm_frame[14], dsm_frame[15]); */ /* * If we have lost signal for at least a second, reset the * format guessing heuristic. */ - if (((frame_time - last_frame_time) > 1000000) && (channel_shift != 0)) + if (((frame_time - dsm_last_frame_time) > 1000000) && (dsm_channel_shift != 0)) dsm_guess_format(true); - /* we have received something we think is a frame */ - last_frame_time = frame_time; + /* we have received something we think is a dsm_frame */ + dsm_last_frame_time = frame_time; - /* if we don't know the frame format, update the guessing state machine */ - if (channel_shift == 0) { + /* if we don't know the dsm_frame format, update the guessing state machine */ + if (dsm_channel_shift == 0) { dsm_guess_format(false); return false; } @@ -337,17 +334,17 @@ dsm_decode(hrt_abstime frame_time, uint16_t *values, uint16_t *num_values) * Each channel is a 16-bit unsigned value containing either a 10- * or 11-bit channel value and a 4-bit channel number, shifted * either 10 or 11 bits. The MSB may also be set to indicate the - * second frame in variants of the protocol where more than + * second dsm_frame in variants of the protocol where more than * seven channels are being transmitted. */ for (unsigned i = 0; i < DSM_FRAME_CHANNELS; i++) { - uint8_t *dp = &frame[2 + (2 * i)]; + uint8_t *dp = &dsm_frame[2 + (2 * i)]; uint16_t raw = (dp[0] << 8) | dp[1]; unsigned channel, value; - if (!dsm_decode_channel(raw, channel_shift, &channel, &value)) + if (!dsm_decode_channel(raw, dsm_channel_shift, &channel, &value)) continue; /* ignore channels out of range */ @@ -359,7 +356,7 @@ dsm_decode(hrt_abstime frame_time, uint16_t *values, uint16_t *num_values) *num_values = channel + 1; /* convert 0-1024 / 0-2048 values to 1000-2000 ppm encoding in a very sloppy fashion */ - if (channel_shift == 11) + if (dsm_channel_shift == 11) value /= 2; value += 998; @@ -390,7 +387,7 @@ dsm_decode(hrt_abstime frame_time, uint16_t *values, uint16_t *num_values) values[channel] = value; } - if (channel_shift == 11) + if (dsm_channel_shift == 11) *num_values |= 0x8000; /* @@ -398,3 +395,70 @@ dsm_decode(hrt_abstime frame_time, uint16_t *values, uint16_t *num_values) */ return true; } + +/** + * Called periodically to check for input data from the DSM UART + * + * The DSM* protocol doesn't provide any explicit framing, + * so we detect dsm frame boundaries by the inter-dsm frame delay. + * The minimum dsm frame spacing is 11ms; with 16 bytes at 115200bps + * dsm frame transmission time is ~1.4ms. + * We expect to only be called when bytes arrive for processing, + * and if an interval of more than 5ms passes between calls, + * the first byte we read will be the first byte of a dsm frame. + * In the case where byte(s) are dropped from a dsm frame, this also + * provides a degree of protection. Of course, it would be better + * if we didn't drop bytes... + * Upon receiving a full dsm frame we attempt to decode it. + * + * @param[out] values pointer to per channel array of decoded values + * @param[out] num_values pointer to number of raw channel values returned + * @return true=decoded raw channel values updated, false=no update + */ +bool +dsm_input(uint16_t *values, uint16_t *num_values) +{ + ssize_t ret; + hrt_abstime now; + + /* + */ + now = hrt_absolute_time(); + + if ((now - dsm_last_rx_time) > 5000) { + if (dsm_partial_frame_count > 0) { + dsm_frame_drops++; + dsm_partial_frame_count = 0; + } + } + + /* + * Fetch bytes, but no more than we would need to complete + * the current dsm frame. + */ + ret = read(dsm_fd, &dsm_frame[dsm_partial_frame_count], DSM_FRAME_SIZE - dsm_partial_frame_count); + + /* if the read failed for any reason, just give up here */ + if (ret < 1) + return false; + + dsm_last_rx_time = now; + + /* + * Add bytes to the current dsm frame + */ + dsm_partial_frame_count += ret; + + /* + * If we don't have a full dsm frame, return + */ + if (dsm_partial_frame_count < DSM_FRAME_SIZE) + return false; + + /* + * Great, it looks like we might have a dsm frame. Go ahead and + * decode it. + */ + dsm_partial_frame_count = 0; + return dsm_decode(now, values, num_values); +} diff --git a/src/modules/px4iofirmware/px4io.h b/src/modules/px4iofirmware/px4io.h index 9eb092a63..b30d155bc 100644 --- a/src/modules/px4iofirmware/px4io.h +++ b/src/modules/px4iofirmware/px4io.h @@ -195,7 +195,7 @@ extern void controls_init(void); extern void controls_tick(void); extern int dsm_init(const char *device); extern bool dsm_input(uint16_t *values, uint16_t *num_values); -extern void dsm_bind(uint16_t cmd, int pulses); +extern void dsm_bind(uint16_t cmd, int pulses); extern int sbus_init(const char *device); extern bool sbus_input(uint16_t *values, uint16_t *num_values); |