4 files changed, 43 insertions, 2 deletions

diff --git a/macros/src/codegen/init.rs b/macros/src/codegen/init.rs
index 6376ce31..6b57add1 100644
--- a/macros/src/codegen/init.rs
+++ b/macros/src/codegen/init.rs
@@ -58,6 +58,24 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> CodegenResult {
             }
         ));
 
+        let monotonic_types: Vec<_> = app
+            .monotonics
+            .iter()
+            .map(|(_, monotonic)| {
+                let mono = &monotonic.ty;
+                quote! {#mono}
+            })
+            .collect();
+        let monotonics = util::monotonics_ident(&name);
+
+        root_init.push(quote!(
+            /// Monotonics used by the system
+            #[allow(non_snake_case)]
+            pub struct #monotonics(
+                #(#monotonic_types),*
+            );
+        ));
+
         let mut locals_pat = None;
         let mut locals_new = None;
         if !init.locals.is_empty() {
@@ -72,10 +90,16 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> CodegenResult {
         let attrs = &init.attrs;
         let stmts = &init.stmts;
         let locals_pat = locals_pat.iter();
+
+        let mut user_init_return = vec![quote! {#name::LateResources}];
+        if !app.monotonics.is_empty() {
+            user_init_return.push(quote! {#name::Monotonics});
+        }
+
         let user_init = Some(quote!(
             #(#attrs)*
             #[allow(non_snake_case)]
-            fn #name(#(#locals_pat,)* #context: #name::Context) -> #name::LateResources {
+            fn #name(#(#locals_pat,)* #context: #name::Context) -> (#(#user_init_return,)*) {
                 #(#stmts)*
             }
         ));
@@ -92,7 +116,7 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> CodegenResult {
         let app_path = quote! {crate::#app_name};
         let locals_new = locals_new.iter();
         let call_init = Some(
-            quote!(let late = #app_path::#name(#(#locals_new,)* #name::Context::new(core.into()));),
+            quote!(let (late, monotonics) = #app_path::#name(#(#locals_new,)* #name::Context::new(core.into()));),
         );
 
         root_init.push(module::codegen(
diff --git a/macros/src/codegen/module.rs b/macros/src/codegen/module.rs
index 2ff4801e..d398a1a8 100644
--- a/macros/src/codegen/module.rs
+++ b/macros/src/codegen/module.rs
@@ -131,11 +131,17 @@ pub fn codegen(
     if let Context::Init = ctxt {
         let init = &app.inits.first().unwrap();
         let late_resources = util::late_resources_ident(&init.name);
+        let monotonics = util::monotonics_ident(&init.name);
 
         items.push(quote!(
             #[doc(inline)]
             pub use super::#late_resources as LateResources;
         ));
+
+        items.push(quote!(
+            #[doc(inline)]
+            pub use super::#monotonics as Monotonics;
+        ));
     }
 
     let doc = match ctxt {
diff --git a/macros/src/codegen/post_init.rs b/macros/src/codegen/post_init.rs
index 5545944d..9174daeb 100644
--- a/macros/src/codegen/post_init.rs
+++ b/macros/src/codegen/post_init.rs
@@ -25,6 +25,9 @@ pub fn codegen(app: &App, analysis: &Analysis) -> Vec<TokenStream2> {
         }
     }
 
+    // Forget the monotonics so they won't be dropped.
+    stmts.push(quote!(core::mem::forget(monotonics);));
+
     // Enable the interrupts -- this completes the `init`-ialization phase
     stmts.push(quote!(rtic::export::interrupt::enable();));
 
diff --git a/macros/src/codegen/util.rs b/macros/src/codegen/util.rs
index fb8f1a84..4273ee2c 100644
--- a/macros/src/codegen/util.rs
+++ b/macros/src/codegen/util.rs
@@ -111,6 +111,14 @@ pub fn late_resources_ident(init: &Ident) -> Ident {
     )
 }
 
+/// Generates a pre-reexport identifier for the "monotonics" struct
+pub fn monotonics_ident(init: &Ident) -> Ident {
+    Ident::new(
+        &format!("{}Monotonics", init.to_string()),
+        Span::call_site(),
+    )
+}
+
 /// Mangle an ident
 pub fn mangle_ident(ident: &Ident) -> Ident {
     Ident::new(