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+# Protocol
+
+This document introduce the protocol used between Basalt Presenter and Basalt Trainer.
+
+## Command Protocol
+
+|Code|Direction|Comment|
+|:---|:---|:---|
+|`0x01`|Presenter-->Trainer|Data was ready. Please Trainer receive it.|
+|`0x02`|Presenter<--Trainer|Data has been received. Please go into next loop.|
+|`0x61`|Presenter<--Trainer|Handshake code (Are Presenter ready?)|
+|`0x62`|Presenter-->Trainer|Handshake code (Presenter is ready)|
+
+### Handshake
+
+At the beginning of execution, Trainer send handshake code to Presenter first and then Presenter send another handshake code to Trainer back. After this, both 2 applications start running.
+
+When Presenter send handshake code back, Presenter should attach some values following it to indicate some essential properties of data which will be passed to Trainer in future. There is a table introduce these properties:
+
+|Data Type|Comment|
+|:---|:---|
+|u8|The pixel kind of image|
+|u32|The width of image|
+|u32|The height of image|
+
+For the all possible values of "pixel kind" in above table, there is also a table:
+
+|Value|Comment|
+|:---|:---|
+|`0x01`|Grayscale represneted by one float32|
+
+## Data Protocol
+
+TODO