Skip /32 AHB prescaler (#228)

* Skip /32 AHB prescaler * Add changelog entry * Fix PR link in changelog
stm32-rs · Apr 5, 2023 · 8de7c8d · 8de7c8d
1 parent 0930a37
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -27,6 +27,8 @@ forget to update the links at the bottom of the changelog as well.-->
 
 ### Fixes
 
+- Correct calculation of AHB prescaler for factors > 16 ([#228])
+
 ### Documentation
 
 ## [v0.10.0] - 2022-08-15
@@ -188,6 +190,7 @@ _Not yet tracked in this changelog._
 <!-- Links to pull requests and issues. -->
 
 [#226]: https://github.com/stm32-rs/stm32l0xx-hal/pull/226
+[#228]: https://github.com/stm32-rs/stm32l0xx-hal/pull/228
 [#224]: https://github.com/stm32-rs/stm32l0xx-hal/pull/224
 [#221]: https://github.com/stm32-rs/stm32l0xx-hal/pull/221
 [#220]: https://github.com/stm32-rs/stm32l0xx-hal/pull/218

diff --git a/src/rcc.rs b/src/rcc.rs
@@ -413,6 +413,8 @@ impl RccExt for RCC {
 
         let ahb_freq = match cfgr.ahb_pre {
             AHBPrescaler::NotDivided => sys_clk,
+            // skip /32
+            pre if pre as u8 & 0b0100 > 0 => sys_clk / (1 << (pre as u8 - 6)),
             pre => sys_clk / (1 << (pre as u8 - 7)),
         };