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| -rw-r--r-- | docs/design.md | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/docs/design.md b/docs/design.md index e7321b6..5d231fc 100644 --- a/docs/design.md +++ b/docs/design.md @@ -37,8 +37,12 @@ binary messages with comments are provided in the source folder When messages are sent out by either side, they are prefixed with a single `0xff` byte to identify the start of a message. If a message contains a literal -`0xff` byte, it will be escaped by the send function by sending the `0xff` byte -twice. +`0xff` byte, it will be escaped by sending the `0xff` byte twice. When the +parser is done receiving a message, it goes into "idle mode". In this mode, all +data is ignored (including double `0xff` bytes), until a single `0xff` byte +followed by any other byte is received, which will cause the parser to parse +incoming data normally again. This approach of a "idle" and "normal" mode was +chosen to make the parser more resilient to serial noise. All data that is sent starts with an opcode to represent the message type, and a message id to uniquely identify each message for the purpose of replying to a @@ -66,6 +70,11 @@ Other important details: - Messages are buffered until complete, so this protocol should be used over unbuffered serial connections only. +A complete list of commands and the additional data they send is located in the +`shared/protocol.h` source file, and is well documented using Doxygen comments. +The protocol implementation is written in portable C, and is used by both the +client and server side to send and receive data. + # Asynchronous QT Serial port The serial data communication is done in an asynchronous manner, which allows the program to efficiently handle data that is arriving on a serial port. |