stm32/wl: add stub APB3 to get it to build.

Completely untested.

embassy-stm32/src/rcc/mod.rs

@@ -10,6 +10,8 @@ pub struct Clocks {
     pub sys: Hertz,
     pub apb1: Hertz,
     pub apb2: Hertz,
+    #[cfg(rcc_wl5)]
+    pub apb3: Hertz,
 
     pub apb1_tim: Hertz,
     pub apb2_tim: Hertz,

embassy-stm32/src/rcc/wl5x/mod.rs

@@ -190,6 +190,9 @@ impl RccExt for RCC {
             }
         };
 
+        // TODO: completely untested
+        let apb3_freq = ahb_freq;
+
         Clocks {
             sys: sys_clk.hz(),
             ahb1: ahb_freq.hz(),
@@ -197,6 +200,7 @@ impl RccExt for RCC {
             ahb3: ahb_freq.hz(),
             apb1: apb1_freq.hz(),
             apb2: apb2_freq.hz(),
+            apb3: apb3_freq.hz(),
             apb1_tim: apb1_tim_freq.hz(),
             apb2_tim: apb2_tim_freq.hz(),
         }

examples/stm32wl55/Cargo.toml

@@ -26,7 +26,7 @@ defmt = "0.2.0"
 defmt-rtt = "0.2.0"
 
 cortex-m = "0.7.1"
-cortex-m-rt = "0.6.14"
+cortex-m-rt = "0.7.0"
 embedded-hal = { version = "0.2.4" }
 panic-probe = { version = "0.2.0", features= ["print-defmt"] }
 futures = { version = "0.3.8", default-features = false, features = ["async-await"] }