add mode module with basic defintions

satrs-core/src/mode.rs

@@ -0,0 +1,25 @@
+use crate::tmtc::TargetId;
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct ModePair {
+    mode: u32,
+    submode: u16,
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct ModeCommand {
+    address: TargetId,
+    mode: ModePair,
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub enum ModeRequest {
+    SetMode(ModeCommand),
+    ReadMode(TargetId),
+    AnnounceMode(TargetId),
+    AnnounceModeRecursive(TargetId),
+}