fix(dshot): set telemetry bit on DShot commands

Bluejay and BLHeli_S ignore commands unless the tlm bit is set, so EDT enable never latched. ESC_INFO keeps it clear: AM32 answers the bit with a KISS frame on the same UART as the EEPROM dump and aborts that frame when the dump starts, so the response would begin with a truncated frame.

Signed-off-by: Jacob Dahl <dahl.jakejacob@gmail.com>

src/drivers/dshot/DShot.cpp

@@ -398,7 +398,11 @@ void DShot::update_motor_commands(int num_outputs)
 			command_sent = true;
 		}
 
-		up_dshot_motor_command(i, command, false);
+		// Bluejay/BLHeli_S discard commands unless the tlm bit is set. It stays clear on commands answered
+		// over the telemetry UART: AM32 reads it as a KISS request and starts that frame on the same wire,
+		// then aborts it a few loop iterations later to send the EEPROM dump.
+		const bool request_telemetry = command != DSHOT_CMD_MOTOR_STOP && !_current_command.expect_response;
+		up_dshot_motor_command(i, command, request_telemetry);
 	}
 
 	if (command_sent) {

src/drivers/dshot/DShotTelemetry.cpp

@@ -278,6 +278,8 @@ TelemetryStatus DShotTelemetry::decodeTelemetryResponse(uint8_t *buffer, int len
 
 void DShotTelemetry::setExpectCommandResponse(int motor_index, uint16_t command)
 {
+	// Earlier commands sent with the tlm bit set leave KISS frames in the RX FIFO.
+	_uart.flush();
 	_command_response_motor_index = motor_index;
 	_command_response_command = command;
 	_command_response_start = hrt_absolute_time();