Documenting code and structure of the telecommands #90

docs/telecommands.rst

@@ -13,7 +13,10 @@ Authentication
 All the telecommands classified as private use an HMAC authentication scheme. Every
 type of private telecommand has a unique 16-digit ASCII character key that with the
 telecommand sequence (or message) generates an 160-bits (20-bytes) hash sequence to
-be transmitted together with the packet payload. The used hash algorithm is the SHA-1.
+be transmitted together with the packet payload. The used hash algorithm is the SHA-1. [3]_
+
+.. image:: img/hmac.png
+   :width: 500
 
 Telecommands
 ============
@@ -53,3 +56,31 @@ Telecommands
 Structure of the packages 
 =========================
 
+Every package payload countains its ID [1 byte], the source callsign (source address of the ground station) [7 bytes] and the package content (data) [up to 212 bytes]. This las tone can either have none or many parameters depending on the funtion of the telecommand.
+
+The communication protocol used is a python variation of the NGHam [1]_: the PyNGHam [2]_.
+
+.. image:: img/ngham.png
+   :width: 300
+
+Telecommands Code
+=================
+
+The Spacelab Transmitter has a generic telecommand class with these functions:
+
+- **generate**: which generate the telecommand payload;
+- **set_id**: which sets a new ID for the telecommand;
+- **get_id**: which gets the ID of the telecommand;
+- **set_name**: which sets a new name for the telecommand;
+- **get_name**: which gets the name of the telecommand;
+- **_prepare_callsign**: which prepares a callsign for a transmission.
+
+Each telecommand has its own class with the Telecommand class working as a "superclass" with 14 telecommands classes working as "subclasses" (this process is called "inheritance" in object-oriented programming).
+
+References
+==========
+
+
+.. [1] https://github.com/skagmo/ngham
+.. [2] https://github.com/mgm8/pyngham
+.. [3] https://github.com/spacelab-ufsc/floripasat2-doc