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| -rw-r--r-- | docs/Protocol.md | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/docs/Protocol.md b/docs/Protocol.md index 5eccdb4f..a8aa9682 100644 --- a/docs/Protocol.md +++ b/docs/Protocol.md @@ -130,23 +130,24 @@ Message Block Contents Each message block sent from host to firmware contains a series of zero or more message commands in its contents. Each command starts -with a Variable Length Quantity (VLQ) encoded command-id followed by -zero or more VLQ parameters for the given command. So, the contents of -an example message block might look like: +with a Variable Length Quantity (VLQ) encoded integer command-id +followed by zero or more VLQ parameters for the given command. So, the +contents of an example message block might look like: ``` <id_cmd_a><param1><id_cmd_b><param1><param2><id_cmd_c><id_cmd_d> ``` In order to encode and parse the message contents, both the host and -firmware must agree on a "data dictionary". The data dictionary -associates high-level commands with specific integer command-ids along -with the number of parameters that the command takes. When processing -the data, the parser will know to expect a specific number of VLQ -encoded parameters following a given command. So, in the above -example, both the host and firmware would know that "id_cmd_a" is -always followed by exactly one parameter, "id_cmd_b" two parameters, -and "id_cmd_c" / "id_cmd_d" zero parameters. +firmware must agree on the number of parameters each command has. So, +in the above example, both the host and firmware would know that +"id_cmd_a" is always followed by exactly one parameter, "id_cmd_b" two +parameters, and "id_cmd_c" / "id_cmd_d" zero parameters. The host and +firmware share a "data dictionary" that associates high-level commands +with specific integer command-ids along with the number of parameters +that the command takes. When processing the data, the parser will know +to expect a specific number of VLQ encoded parameters following a +given command. The message contents for blocks sent from firmware to host follow the same format. The identifiers in these messages are "response ids", but |