Describe multi telemetry protocol

Multiprotocol/Multiprotocol.h

@@ -523,3 +523,61 @@ Serial: 100000 Baud 8e2      _ xxxx xxxx p --
 	2047	+125%
    Channels bits are concatenated to fit in 22 bytes like in SBUS protocol
 */
+/*
+  Multiprotocol telemetry definition
+
+  Serial: 100000 Baud 8e2 (same as input)
+
+  TLV Protocol (type, length, value), allows a TX to ignore unknown messages
+
+  Format: header (4 byte) + data (variable)
+
+   [0] = 'M' (0x4d)
+   [1] = 'P' (0x50)
+
+
+   The first byte is deliberatly chosen to be different from other telemetry protocols
+   (e.g. 0xAA for DSM/Multi, 0xAA for FlySky and 0x7e for Frsky) to allow a TX to detect
+   the telemetry format of older versions
+
+   [2] Type (see below)
+   [3] Length (excluding the 4 header bytes)
+
+   [4-xx] data
+
+
+Type = 0x01 Multimodule Status:
+   [4] Flags
+
+   0x01 = Input signal detected
+   0x02 = Serial mode enabled
+   0x04 = protocol is invalid
+   0x08 = module is in binding mode
+
+   [5-8] uint32  - version of multi code
+
+   more information can be added by specifing a longer length of the type, the TX will just ignore these bytes
+
+
+Type 0x02 Frksy S.port telemetry
+Type 0x03 Frsky Hub telemetry
+
+	*No* usual frsky byte stuffing
+
+
+Type 0x04 Spektrum telemetry data
+   data[0] RSSI
+   data[1-15] telemetry data
+
+Type 0x05 DSM bind data
+	data[0-16] DSM bind data
+
+    technically DSM bind data is only 10 bytes but multi send 16
+    like with telemtry, check length field)
+
+Type 0x06 Flysky AFHDS2 telemetry data
+   length: 29
+   data[0] = RSSI value
+   data[1-28] telemetry data
+
+*/