diff --git a/CHANGELOG.md b/CHANGELOG.md
index f19723a..ca9bc2c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- Fixed encoding of IN instruction with `bit_count` == 32
+
 ## [0.2.1] [Crates.io](https://crates.io/crates/pio-rs/0.2.1) [Github](https://github.com/rp-rs/pio-rs/releases/tag/v0.2.1)
 
 - Fixed the search path for `pio_file` when using relative paths
diff --git a/src/lib.rs b/src/lib.rs
index e5de4c7..b40a5c8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -233,7 +233,7 @@ impl InstructionOperands {
                     *index | (if *relative { 0b10000 } else { 0 }),
                 )
             }
-            InstructionOperands::IN { source, bit_count } => (*source as u8, *bit_count),
+            InstructionOperands::IN { source, bit_count } => (*source as u8, *bit_count & 0b11111),
             InstructionOperands::OUT {
                 destination,
                 bit_count,