diff options
Diffstat (limited to 'src/modules/mavlink/mavlink_messages.cpp')
| -rw-r--r-- | src/modules/mavlink/mavlink_messages.cpp | 48 |
1 files changed, 47 insertions, 1 deletions
diff --git a/src/modules/mavlink/mavlink_messages.cpp b/src/modules/mavlink/mavlink_messages.cpp index bed915bbe..978aee118 100644 --- a/src/modules/mavlink/mavlink_messages.cpp +++ b/src/modules/mavlink/mavlink_messages.cpp @@ -1719,7 +1719,53 @@ protected: msg.chan16_raw = (rc.channel_count > 15) ? rc.values[15] : UINT16_MAX; msg.chan17_raw = (rc.channel_count > 16) ? rc.values[16] : UINT16_MAX; msg.chan18_raw = (rc.channel_count > 17) ? rc.values[17] : UINT16_MAX; - msg.rssi = rc.rssi; + + /* RSSI has a max value of 100, and when Spektrum or S.BUS are + * available, the RSSI field is invalid, as they do not provide + * an RSSI measurement. Use an out of band magic value to signal + * these digital ports. XXX revise MAVLink spec to address this. + * One option would be to use the top bit to toggle between RSSI + * and input source mode. + * + * Full RSSI field: 0b 1 111 1111 + * + * ^ If bit is set, RSSI encodes type + RSSI + * + * ^ These three bits encode a total of 8 + * digital RC input types. + * 0: PPM, 1: SBUS, 2: Spektrum, 2: ST24 + * ^ These four bits encode a total of + * 16 RSSI levels. 15 = full, 0 = no signal + * + */ + + /* Initialize RSSI with the special mode level flag */ + msg.rssi = (1 << 7); + + /* Set RSSI */ + msg.rssi |= (rc.rssi <= 100) ? ((rc.rssi / 7) + 1) : 15; + + switch (rc.input_source) { + case RC_INPUT_SOURCE_PX4FMU_PPM: + /* fallthrough */ + case RC_INPUT_SOURCE_PX4IO_PPM: + msg.rssi |= (0 << 4); + break; + case RC_INPUT_SOURCE_PX4IO_SPEKTRUM: + msg.rssi |= (1 << 4); + break; + case RC_INPUT_SOURCE_PX4IO_SBUS: + msg.rssi |= (2 << 4); + break; + case RC_INPUT_SOURCE_PX4IO_ST24: + msg.rssi |= (3 << 4); + break; + } + + if (rc.rc_lost) { + /* RSSI is by definition zero */ + msg.rssi = 0; + } _mavlink->send_message(MAVLINK_MSG_ID_RC_CHANNELS, &msg); } |