diff --git a/CHANGELOG.md b/CHANGELOG.md
index 61aa417..08a3dbd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Updated the `cast` dependency from 0.2 to 0.3
 - Updated `stm32f0` peripheral access crate from 0.14 to 0.15
+- Use `critical_section::CriticalSection` for GPIO configuration (breaking change)
 
 ### Added
 
diff --git a/Cargo.toml b/Cargo.toml
index dd0b982..08642a7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -33,6 +33,7 @@ targets = ["thumbv6m-none-eabi"]
 bare-metal = { version = "1.0.0" }
 cast = "0.3"
 cortex-m = "0.7"
+critical-section = "1.0"
 embedded-hal = { version = "0.2", features = ["unproven"] }
 stm32f0 = "0.15"
 nb = "1"
diff --git a/examples/adc_values.rs b/examples/adc_values.rs
index bd7cd8d..351d13f 100644
--- a/examples/adc_values.rs
+++ b/examples/adc_values.rs
@@ -7,8 +7,9 @@ use stm32f0xx_hal as hal;
 
 use crate::hal::{pac, prelude::*};
 
-use cortex_m::{interrupt::Mutex, peripheral::syst::SystClkSource::Core};
+use cortex_m::peripheral::syst::SystClkSource::Core;
 use cortex_m_rt::{entry, exception};
+use critical_section::Mutex;
 
 use core::{cell::RefCell, fmt::Write};
 
@@ -25,7 +26,7 @@ fn main() -> ! {
         hal::pac::Peripherals::take(),
         cortex_m::peripheral::Peripherals::take(),
     ) {
-        cortex_m::interrupt::free(move |cs| {
+        critical_section::with(move |cs| {
             let mut flash = p.FLASH;
             let mut rcc = p.RCC.configure().sysclk(8.mhz()).freeze(&mut flash);
 
@@ -46,8 +47,8 @@ fn main() -> ! {
             syst.enable_interrupt();
 
             // USART1 at PA9 (TX) and PA10(RX)
-            let tx = gpioa.pa9.into_alternate_af1(cs);
-            let rx = gpioa.pa10.into_alternate_af1(cs);
+            let tx = gpioa.pa9.into_alternate_af1(&cs);
+            let rx = gpioa.pa10.into_alternate_af1(&cs);
 
             // Initialiase UART
             let (mut tx, _) =
@@ -74,7 +75,7 @@ fn SysTick() {
     use core::ops::DerefMut;
 
     // Enter critical section
-    cortex_m::interrupt::free(|cs| {
+    critical_section::with(|cs| {
         // Get access to the Mutex protected shared data
         if let Some(ref mut shared) = SHARED.borrow(cs).borrow_mut().deref_mut() {
             // Read temperature data from internal sensor using ADC
diff --git a/examples/blinky.rs b/examples/blinky.rs
index df1c90c..6c1178c 100644
--- a/examples/blinky.rs
+++ b/examples/blinky.rs
@@ -17,7 +17,7 @@ fn main() -> ! {
         let gpioa = p.GPIOA.split(&mut rcc);
 
         // (Re-)configure PA1 as output
-        let mut led = cortex_m::interrupt::free(|cs| gpioa.pa1.into_push_pull_output(cs));
+        let mut led = critical_section::with(|cs| gpioa.pa1.into_push_pull_output(&cs));
 
         loop {
             // Turn PA1 on a million times in a row
diff --git a/examples/blinky_adc.rs b/examples/blinky_adc.rs
index c74c2c3..aec4bdc 100644
--- a/examples/blinky_adc.rs
+++ b/examples/blinky_adc.rs
@@ -17,12 +17,12 @@ fn main() -> ! {
 
         let gpioa = p.GPIOA.split(&mut rcc);
 
-        let (mut led, mut an_in) = cortex_m::interrupt::free(move |cs| {
+        let (mut led, mut an_in) = critical_section::with(move |cs| {
             (
                 // (Re-)configure PA1 as output
-                gpioa.pa1.into_push_pull_output(cs),
+                gpioa.pa1.into_push_pull_output(&cs),
                 // (Re-)configure PA0 as analog input
-                gpioa.pa0.into_analog(cs),
+                gpioa.pa0.into_analog(&cs),
             )
         });
 
diff --git a/examples/blinky_delay.rs b/examples/blinky_delay.rs
index 22fdd52..4b7c2b5 100644
--- a/examples/blinky_delay.rs
+++ b/examples/blinky_delay.rs
@@ -18,7 +18,7 @@ fn main() -> ! {
         let gpioa = p.GPIOA.split(&mut rcc);
 
         // (Re-)configure PA1 as output
-        let mut led = cortex_m::interrupt::free(move |cs| gpioa.pa1.into_push_pull_output(cs));
+        let mut led = critical_section::with(move |cs| gpioa.pa1.into_push_pull_output(&cs));
 
         // Get delay provider
         let mut delay = Delay::new(cp.SYST, &rcc);
diff --git a/examples/blinky_multiple.rs b/examples/blinky_multiple.rs
index a4939ea..bb94558 100644
--- a/examples/blinky_multiple.rs
+++ b/examples/blinky_multiple.rs
@@ -18,12 +18,12 @@ fn main() -> ! {
         let gpioa = p.GPIOA.split(&mut rcc);
         let gpiob = p.GPIOB.split(&mut rcc);
 
-        let (led1, led2) = cortex_m::interrupt::free(move |cs| {
+        let (led1, led2) = critical_section::with(move |cs| {
             (
                 // (Re-)configure PA1 as output
-                gpioa.pa1.into_push_pull_output(cs),
+                gpioa.pa1.into_push_pull_output(&cs),
                 // (Re-)configure PB1 as output
-                gpiob.pb1.into_push_pull_output(cs),
+                gpiob.pb1.into_push_pull_output(&cs),
             )
         });
 
diff --git a/examples/blinky_timer.rs b/examples/blinky_timer.rs
index 994dcc0..50f74c3 100644
--- a/examples/blinky_timer.rs
+++ b/examples/blinky_timer.rs
@@ -17,7 +17,7 @@ fn main() -> ! {
         let gpioa = p.GPIOA.split(&mut rcc);
 
         // (Re-)configure PA1 as output
-        let mut led = cortex_m::interrupt::free(move |cs| gpioa.pa1.into_push_pull_output(cs));
+        let mut led = critical_section::with(move |cs| gpioa.pa1.into_push_pull_output(&cs));
 
         // Set up a timer expiring after 1s
         let mut timer = Timer::tim1(p.TIM1, Hertz(1), &mut rcc);
diff --git a/examples/blinky_timer_irq.rs b/examples/blinky_timer_irq.rs
index 9504638..5ef9c0e 100644
--- a/examples/blinky_timer_irq.rs
+++ b/examples/blinky_timer_irq.rs
@@ -16,7 +16,8 @@ use crate::hal::{
 use cortex_m_rt::entry;
 
 use core::cell::RefCell;
-use cortex_m::{interrupt::Mutex, peripheral::Peripherals as c_m_Peripherals};
+use cortex_m::peripheral::Peripherals as c_m_Peripherals;
+use critical_section::Mutex;
 
 // A type definition for the GPIO pin to be used for our LED
 type LEDPIN = gpioa::PA5<Output<PushPull>>;
@@ -35,14 +36,14 @@ fn TIM7() {
     static mut INT: Option<Timer<TIM7>> = None;
 
     let led = LED.get_or_insert_with(|| {
-        cortex_m::interrupt::free(|cs| {
+        critical_section::with(|cs| {
             // Move LED pin here, leaving a None in its place
             GLED.borrow(cs).replace(None).unwrap()
         })
     });
 
     let int = INT.get_or_insert_with(|| {
-        cortex_m::interrupt::free(|cs| {
+        critical_section::with(|cs| {
             // Move LED pin here, leaving a None in its place
             GINT.borrow(cs).replace(None).unwrap()
         })
@@ -55,7 +56,7 @@ fn TIM7() {
 #[entry]
 fn main() -> ! {
     if let (Some(mut p), Some(cp)) = (Peripherals::take(), c_m_Peripherals::take()) {
-        cortex_m::interrupt::free(move |cs| {
+        critical_section::with(move |cs| {
             let mut rcc = p
                 .RCC
                 .configure()
@@ -68,7 +69,7 @@ fn main() -> ! {
             let gpioa = p.GPIOA.split(&mut rcc);
 
             // (Re-)configure PA5 as output
-            let led = gpioa.pa5.into_push_pull_output(cs);
+            let led = gpioa.pa5.into_push_pull_output(&cs);
 
             // Move the pin into our global storage
             *GLED.borrow(cs).borrow_mut() = Some(led);
diff --git a/examples/dac.rs b/examples/dac.rs
index 6ba0d23..f20676d 100644
--- a/examples/dac.rs
+++ b/examples/dac.rs
@@ -24,7 +24,7 @@ fn main() -> ! {
         let mut rcc = dp.RCC.configure().sysclk(8.mhz()).freeze(&mut dp.FLASH);
         let gpioa = dp.GPIOA.split(&mut rcc);
 
-        let pa4 = cortex_m::interrupt::free(move |cs| gpioa.pa4.into_analog(cs));
+        let pa4 = critical_section::with(move |cs| gpioa.pa4.into_analog(&cs));
 
         let mut dac = dac(dp.DAC, pa4, &mut rcc);
 
diff --git a/examples/flash_systick.rs b/examples/flash_systick.rs
index 05589de..fb0e37d 100644
--- a/examples/flash_systick.rs
+++ b/examples/flash_systick.rs
@@ -7,8 +7,9 @@ use stm32f0xx_hal as hal;
 
 use crate::hal::{gpio::*, pac, prelude::*};
 
-use cortex_m::{interrupt::Mutex, peripheral::syst::SystClkSource::Core, Peripherals};
+use cortex_m::{peripheral::syst::SystClkSource::Core, Peripherals};
 use cortex_m_rt::{entry, exception};
+use critical_section::Mutex;
 
 use core::cell::RefCell;
 use core::ops::DerefMut;
@@ -19,13 +20,13 @@ static GPIO: Mutex<RefCell<Option<gpioa::PA1<Output<PushPull>>>>> = Mutex::new(R
 #[entry]
 fn main() -> ! {
     if let (Some(mut p), Some(cp)) = (pac::Peripherals::take(), Peripherals::take()) {
-        cortex_m::interrupt::free(move |cs| {
+        critical_section::with(move |cs| {
             let mut rcc = p.RCC.configure().sysclk(48.mhz()).freeze(&mut p.FLASH);
 
             let gpioa = p.GPIOA.split(&mut rcc);
 
             // (Re-)configure PA1 as output
-            let led = gpioa.pa1.into_push_pull_output(cs);
+            let led = gpioa.pa1.into_push_pull_output(&cs);
 
             // Transfer GPIO into a shared structure
             *GPIO.borrow(cs).borrow_mut() = Some(led);
@@ -62,7 +63,7 @@ fn SysTick() {
     static mut STATE: u8 = 1;
 
     // Enter critical section
-    cortex_m::interrupt::free(|cs| {
+    critical_section::with(|cs| {
         // Borrow access to our GPIO pin from the shared structure
         if let Some(ref mut led) = *GPIO.borrow(cs).borrow_mut().deref_mut() {
             // Check state variable, keep LED off most of the time and turn it on every 10th tick
diff --git a/examples/flash_systick_fancier.rs b/examples/flash_systick_fancier.rs
index de4ca2e..f79962e 100644
--- a/examples/flash_systick_fancier.rs
+++ b/examples/flash_systick_fancier.rs
@@ -7,8 +7,9 @@ use stm32f0xx_hal as hal;
 
 use crate::hal::{gpio::*, pac, prelude::*};
 
-use cortex_m::{interrupt::Mutex, peripheral::syst::SystClkSource::Core, Peripherals};
+use cortex_m::{peripheral::syst::SystClkSource::Core, Peripherals};
 use cortex_m_rt::{entry, exception};
+use critical_section::Mutex;
 
 use core::cell::RefCell;
 use core::mem::swap;
@@ -22,14 +23,14 @@ static GPIO: Mutex<RefCell<Option<LEDPIN>>> = Mutex::new(RefCell::new(None));
 #[entry]
 fn main() -> ! {
     if let (Some(mut p), Some(cp)) = (pac::Peripherals::take(), Peripherals::take()) {
-        cortex_m::interrupt::free(move |cs| {
+        critical_section::with(move |cs| {
             let mut rcc = p.RCC.configure().sysclk(48.mhz()).freeze(&mut p.FLASH);
 
             // Get access to individual pins in the GPIO port
             let gpioa = p.GPIOB.split(&mut rcc);
 
             // (Re-)configure the pin connected to our LED as output
-            let led = gpioa.pb3.into_push_pull_output(cs);
+            let led = gpioa.pb3.into_push_pull_output(&cs);
 
             // Transfer GPIO into a shared structure
             swap(&mut Some(led), &mut GPIO.borrow(cs).borrow_mut());
@@ -88,7 +89,7 @@ fn SysTick() {
     // Otherwise move it out of the Mutex protected shared region into our exception handler
     else {
         // Enter critical section
-        cortex_m::interrupt::free(|cs| {
+        critical_section::with(|cs| {
             // Swap globally stored data with SysTick private data
             swap(LED, &mut GPIO.borrow(cs).borrow_mut());
         });
diff --git a/examples/i2c_find_address.rs b/examples/i2c_find_address.rs
index 4ca8454..3a5b779 100644
--- a/examples/i2c_find_address.rs
+++ b/examples/i2c_find_address.rs
@@ -14,15 +14,15 @@ use cortex_m_rt::entry;
 #[entry]
 fn main() -> ! {
     if let Some(p) = pac::Peripherals::take() {
-        cortex_m::interrupt::free(move |cs| {
+        critical_section::with(move |cs| {
             let mut flash = p.FLASH;
             let mut rcc = p.RCC.configure().freeze(&mut flash);
 
             let gpiob = p.GPIOB.split(&mut rcc);
 
             // Configure pins for I2C
-            let sda = gpiob.pb7.into_alternate_af1(cs);
-            let scl = gpiob.pb8.into_alternate_af1(cs);
+            let sda = gpiob.pb7.into_alternate_af1(&cs);
+            let scl = gpiob.pb8.into_alternate_af1(&cs);
 
             // Configure I2C with 100kHz rate
             let mut i2c = I2c::i2c1(p.I2C1, (scl, sda), 100.khz(), &mut rcc);
diff --git a/examples/led_hal_button_irq.rs b/examples/led_hal_button_irq.rs
index a635809..7ed70ef 100644
--- a/examples/led_hal_button_irq.rs
+++ b/examples/led_hal_button_irq.rs
@@ -12,8 +12,9 @@ use crate::hal::{
     prelude::*,
 };
 
-use cortex_m::{interrupt::Mutex, peripheral::Peripherals as c_m_Peripherals};
+use cortex_m::peripheral::Peripherals as c_m_Peripherals;
 use cortex_m_rt::entry;
+use critical_section::Mutex;
 
 use core::{cell::RefCell, ops::DerefMut};
 
@@ -29,7 +30,7 @@ static INT: Mutex<RefCell<Option<EXTI>>> = Mutex::new(RefCell::new(None));
 #[entry]
 fn main() -> ! {
     if let (Some(p), Some(cp)) = (Peripherals::take(), c_m_Peripherals::take()) {
-        cortex_m::interrupt::free(move |cs| {
+        critical_section::with(move |cs| {
             // Enable clock for SYSCFG
             let rcc = p.RCC;
             rcc.apb2enr.modify(|_, w| w.syscfgen().set_bit());
@@ -43,10 +44,10 @@ fn main() -> ! {
             let exti = p.EXTI;
 
             // Configure PB1 as input (button)
-            let _ = gpiob.pb1.into_pull_down_input(cs);
+            let _ = gpiob.pb1.into_pull_down_input(&cs);
 
             // Configure PA1 as output (LED)
-            let mut led = gpioa.pa1.into_push_pull_output(cs);
+            let mut led = gpioa.pa1.into_push_pull_output(&cs);
 
             // Turn off LED
             led.set_low().ok();
@@ -88,7 +89,7 @@ fn main() -> ! {
 #[interrupt]
 fn EXTI0_1() {
     // Enter critical section
-    cortex_m::interrupt::free(|cs| {
+    critical_section::with(|cs| {
         // Obtain all Mutex protected resources
         if let (&mut Some(ref mut led), &mut Some(ref mut delay), &mut Some(ref mut exti)) = (
             LED.borrow(cs).borrow_mut().deref_mut(),
diff --git a/examples/pwm.rs b/examples/pwm.rs
index 8990f2f..08a777f 100644
--- a/examples/pwm.rs
+++ b/examples/pwm.rs
@@ -18,10 +18,10 @@ fn main() -> ! {
         let mut rcc = dp.RCC.configure().sysclk(8.mhz()).freeze(&mut dp.FLASH);
 
         let gpioa = dp.GPIOA.split(&mut rcc);
-        let channels = cortex_m::interrupt::free(move |cs| {
+        let channels = critical_section::with(move |cs| {
             (
-                gpioa.pa8.into_alternate_af2(cs),
-                gpioa.pa9.into_alternate_af2(cs),
+                gpioa.pa8.into_alternate_af2(&cs),
+                gpioa.pa9.into_alternate_af2(&cs),
             )
         });
 
diff --git a/examples/pwm_complementary.rs b/examples/pwm_complementary.rs
index f190c20..1280d77 100644
--- a/examples/pwm_complementary.rs
+++ b/examples/pwm_complementary.rs
@@ -18,10 +18,10 @@ fn main() -> ! {
         let mut rcc = dp.RCC.configure().sysclk(8.mhz()).freeze(&mut dp.FLASH);
 
         let gpioa = dp.GPIOA.split(&mut rcc);
-        let channels = cortex_m::interrupt::free(move |cs| {
+        let channels = critical_section::with(move |cs| {
             (
-                gpioa.pa8.into_alternate_af2(cs), // on TIM1_CH1
-                gpioa.pa7.into_alternate_af2(cs), // on TIM1_CH1N
+                gpioa.pa8.into_alternate_af2(&cs), // on TIM1_CH1
+                gpioa.pa7.into_alternate_af2(&cs), // on TIM1_CH1N
             )
         });
 
diff --git a/examples/serial_echo.rs b/examples/serial_echo.rs
index d0c70d3..94a4220 100644
--- a/examples/serial_echo.rs
+++ b/examples/serial_echo.rs
@@ -17,10 +17,10 @@ fn main() -> ! {
 
         let gpioa = p.GPIOA.split(&mut rcc);
 
-        let (tx, rx) = cortex_m::interrupt::free(move |cs| {
+        let (tx, rx) = critical_section::with(move |cs| {
             (
-                gpioa.pa9.into_alternate_af1(cs),
-                gpioa.pa10.into_alternate_af1(cs),
+                gpioa.pa9.into_alternate_af1(&cs),
+                gpioa.pa10.into_alternate_af1(&cs),
             )
         });
 
diff --git a/examples/serial_spi_bridge.rs b/examples/serial_spi_bridge.rs
index b3bacd5..d8a7ee7 100644
--- a/examples/serial_spi_bridge.rs
+++ b/examples/serial_spi_bridge.rs
@@ -36,15 +36,15 @@ fn main() -> ! {
 
         let gpioa = p.GPIOA.split(&mut rcc);
 
-        let (sck, miso, mosi, tx, rx) = cortex_m::interrupt::free(move |cs| {
+        let (sck, miso, mosi, tx, rx) = critical_section::with(move |cs| {
             (
                 // SPI pins
-                gpioa.pa5.into_alternate_af0(cs),
-                gpioa.pa6.into_alternate_af0(cs),
-                gpioa.pa7.into_alternate_af0(cs),
+                gpioa.pa5.into_alternate_af0(&cs),
+                gpioa.pa6.into_alternate_af0(&cs),
+                gpioa.pa7.into_alternate_af0(&cs),
                 // USART pins
-                gpioa.pa9.into_alternate_af1(cs),
-                gpioa.pa10.into_alternate_af1(cs),
+                gpioa.pa9.into_alternate_af1(&cs),
+                gpioa.pa10.into_alternate_af1(&cs),
             )
         });
 
diff --git a/examples/serial_stopwatch.rs b/examples/serial_stopwatch.rs
index 37c5127..19697f4 100644
--- a/examples/serial_stopwatch.rs
+++ b/examples/serial_stopwatch.rs
@@ -15,8 +15,9 @@ use core::cell::RefCell;
 use core::fmt::Write as _;
 use core::ops::DerefMut;
 
-use cortex_m::{interrupt::Mutex, peripheral::Peripherals as c_m_Peripherals};
+use cortex_m::peripheral::Peripherals as c_m_Peripherals;
 use cortex_m_rt::entry;
+use critical_section::Mutex;
 
 // Make timer interrupt registers globally available
 static GINT: Mutex<RefCell<Option<Timer<TIM7>>>> = Mutex::new(RefCell::new(None));
@@ -36,7 +37,7 @@ static TIME: Mutex<RefCell<Time>> = Mutex::new(RefCell::new(Time {
 // interrupt trips when the timer timed out
 #[interrupt]
 fn TIM7() {
-    cortex_m::interrupt::free(|cs| {
+    critical_section::with(|cs| {
         // Move LED pin here, leaving a None in its place
         GINT.borrow(cs)
             .borrow_mut()
@@ -57,14 +58,14 @@ fn TIM7() {
 #[entry]
 fn main() -> ! {
     if let (Some(p), Some(cp)) = (Peripherals::take(), c_m_Peripherals::take()) {
-        let mut serial = cortex_m::interrupt::free(move |cs| {
+        let mut serial = critical_section::with(move |cs| {
             let mut flash = p.FLASH;
             let mut rcc = p.RCC.configure().sysclk(48.mhz()).freeze(&mut flash);
 
             // Use USART2 with PA2 and PA3 as serial port
             let gpioa = p.GPIOA.split(&mut rcc);
-            let tx = gpioa.pa2.into_alternate_af1(cs);
-            let rx = gpioa.pa3.into_alternate_af1(cs);
+            let tx = gpioa.pa2.into_alternate_af1(&cs);
+            let rx = gpioa.pa3.into_alternate_af1(&cs);
 
             // Set up a timer expiring every millisecond
             let mut timer = Timer::tim7(p.TIM7, 1000.hz(), &mut rcc);
@@ -98,7 +99,7 @@ fn main() -> ! {
             // Wait for reception of a single byte
             let received = nb::block!(serial.read()).unwrap();
 
-            let time = cortex_m::interrupt::free(|cs| {
+            let time = critical_section::with(|cs| {
                 let mut time = TIME.borrow(cs).borrow_mut();
 
                 // If we received a 0, reset the time
diff --git a/examples/spi_hal_apa102c.rs b/examples/spi_hal_apa102c.rs
index f3c2007..99b9c28 100644
--- a/examples/spi_hal_apa102c.rs
+++ b/examples/spi_hal_apa102c.rs
@@ -28,11 +28,11 @@ fn main() -> ! {
         let gpioa = p.GPIOA.split(&mut rcc);
 
         // Configure pins for SPI
-        let (sck, miso, mosi) = cortex_m::interrupt::free(move |cs| {
+        let (sck, miso, mosi) = critical_section::with(move |cs| {
             (
-                gpioa.pa5.into_alternate_af0(cs),
-                gpioa.pa6.into_alternate_af0(cs),
-                gpioa.pa7.into_alternate_af0(cs),
+                gpioa.pa5.into_alternate_af0(&cs),
+                gpioa.pa6.into_alternate_af0(&cs),
+                gpioa.pa7.into_alternate_af0(&cs),
             )
         });
 
diff --git a/examples/usb_serial.rs b/examples/usb_serial.rs
index 49afe55..e9a86a5 100644
--- a/examples/usb_serial.rs
+++ b/examples/usb_serial.rs
@@ -35,7 +35,7 @@ fn main() -> ! {
 
     // Configure the on-board LED (LD3, green)
     let gpiob = dp.GPIOB.split(&mut rcc);
-    let mut led = cortex_m::interrupt::free(|cs| gpiob.pb3.into_push_pull_output(cs));
+    let mut led = critical_section::with(|cs| gpiob.pb3.into_push_pull_output(&cs));
     led.set_low().ok(); // Turn off
 
     let gpioa = dp.GPIOA.split(&mut rcc);
diff --git a/examples/watchdog.rs b/examples/watchdog.rs
index bcd265e..5e94fea 100644
--- a/examples/watchdog.rs
+++ b/examples/watchdog.rs
@@ -30,7 +30,7 @@ fn main() -> ! {
         let mut delay = Delay::new(cp.SYST, &rcc);
 
         // Configure serial TX pin
-        let tx = cortex_m::interrupt::free(move |cs| gpioa.pa9.into_alternate_af1(cs));
+        let tx = critical_section::with(move |cs| gpioa.pa9.into_alternate_af1(&cs));
 
         // Obtain a serial peripheral with for unidirectional communication
         let mut serial = Serial::usart1tx(p.USART1, tx, 115_200.bps(), &mut rcc);
diff --git a/src/adc.rs b/src/adc.rs
index edf97a2..f5473a5 100644
--- a/src/adc.rs
+++ b/src/adc.rs
@@ -12,14 +12,14 @@
 //! use crate::hal::prelude::*;
 //! use crate::hal::adc::Adc;
 //!
-//! cortex_m::interrupt::free(|cs| {
+//! critical_section::with(|cs| {
 //!     let mut p = pac::Peripherals::take().unwrap();
 //!     let mut rcc = p.RCC.configure().freeze(&mut p.FLASH);
 //!
 //!     let gpioa = p.GPIOA.split(&mut rcc);
 //!
-//!     let mut led = gpioa.pa1.into_push_pull_pull_output(cs);
-//!     let mut an_in = gpioa.pa0.into_analog(cs);
+//!     let mut led = gpioa.pa1.into_push_pull_pull_output(&cs);
+//!     let mut an_in = gpioa.pa0.into_analog(&cs);
 //!
 //!     let mut delay = Delay::new(cp.SYST, &rcc);
 //!
diff --git a/src/dac.rs b/src/dac.rs
index 4587276..328f0be 100644
--- a/src/dac.rs
+++ b/src/dac.rs
@@ -29,11 +29,11 @@
 //!#[entry]
 //!fn main() -> ! {
 //!    if let (Some(mut dp), Some(_cp)) = (pac::Peripherals::take(), cortex_m::Peripherals::take()) {
-//!        cortex_m::interrupt::free(move |cs| {
+//!        critical_section::with(move |cs| {
 //!            let mut rcc = dp.RCC.configure().sysclk(8.mhz()).freeze(&mut dp.FLASH);
 //!
 //!            let gpioa = dp.GPIOA.split(&mut rcc);
-//!            let mut dac = dac(dp.DAC, gpioa.pa4.into_analog(cs), &mut rcc);
+//!            let mut dac = dac(dp.DAC, gpioa.pa4.into_analog(&cs), &mut rcc);
 //!
 //!            dac.enable();
 //!
diff --git a/src/gpio.rs b/src/gpio.rs
index dd2757e..072085a 100644
--- a/src/gpio.rs
+++ b/src/gpio.rs
@@ -190,7 +190,7 @@ macro_rules! gpio {
                     pac::$GPIOX
                 };
 
-                use cortex_m::interrupt::CriticalSection;
+                use critical_section::CriticalSection;
 
                 use super::{
                     Alternate, Analog, Floating, GpioExt, Input, OpenDrain, Output,
diff --git a/src/serial.rs b/src/serial.rs
index ea8bed9..f157491 100644
--- a/src/serial.rs
+++ b/src/serial.rs
@@ -16,13 +16,13 @@
 //!
 //! use nb::block;
 //!
-//! cortex_m::interrupt::free(|cs| {
+//! critical_section::with(|cs| {
 //!     let rcc = p.RCC.configure().sysclk(48.mhz()).freeze();
 //!
 //!     let gpioa = p.GPIOA.split(&mut rcc);
 //!
-//!     let tx = gpioa.pa9.into_alternate_af1(cs);
-//!     let rx = gpioa.pa10.into_alternate_af1(cs);
+//!     let tx = gpioa.pa9.into_alternate_af1(&cs);
+//!     let rx = gpioa.pa10.into_alternate_af1(&cs);
 //!
 //!     let mut serial = Serial::usart1(p.USART1, (tx, rx), 115_200.bps(), &mut rcc);
 //!
@@ -43,12 +43,12 @@
 //!
 //! use nb::block;
 //!
-//! cortex_m::interrupt::free(|cs| {
+//! critical_section::with(|cs| {
 //!     let rcc = p.RCC.configure().sysclk(48.mhz()).freeze();
 //!
 //!     let gpioa = p.GPIOA.split(&mut rcc);
 //!
-//!     let tx = gpioa.pa9.into_alternate_af1(cs);
+//!     let tx = gpioa.pa9.into_alternate_af1(&cs);
 //!
 //!     let mut serial = Serial::usart1tx(p.USART1, tx, 115_200.bps(), &mut rcc);
 //!
diff --git a/src/spi.rs b/src/spi.rs
index 17eeef7..4b75c7a 100644
--- a/src/spi.rs
+++ b/src/spi.rs
@@ -13,16 +13,16 @@
 //! use crate::hal::prelude::*;
 //! use crate::hal::spi::{Spi, Mode, Phase, Polarity};
 //!
-//! cortex_m::interrupt::free(|cs| {
+//! critical_section::with(|cs| {
 //!     let mut p = pac::Peripherals::take().unwrap();
 //!     let mut rcc = p.RCC.constrain().freeze(&mut p.FLASH);
 //!
 //!     let gpioa = p.GPIOA.split(&mut rcc);
 //!
 //!     // Configure pins for SPI
-//!     let sck = gpioa.pa5.into_alternate_af0(cs);
-//!     let miso = gpioa.pa6.into_alternate_af0(cs);
-//!     let mosi = gpioa.pa7.into_alternate_af0(cs);
+//!     let sck = gpioa.pa5.into_alternate_af0(&cs);
+//!     let miso = gpioa.pa6.into_alternate_af0(&cs);
+//!     let mosi = gpioa.pa7.into_alternate_af0(&cs);
 //!
 //!     // Configure SPI with 1MHz rate
 //!     let mut spi = Spi::spi1(p.SPI1, (sck, miso, mosi), Mode {
diff --git a/src/timers.rs b/src/timers.rs
index 136bc93..ff64e20 100644
--- a/src/timers.rs
+++ b/src/timers.rs
@@ -13,13 +13,13 @@
 //! use crate::hal::timers::*;
 //! use nb::block;
 //!
-//! cortex_m::interrupt::free(|cs| {
+//! critical_section::with(|cs| {
 //!     let mut p = pac::Peripherals::take().unwrap();
 //!     let mut rcc = p.RCC.configure().freeze(&mut p.FLASH);
 //!
 //!     let gpioa = p.GPIOA.split(&mut rcc);
 //!
-//!     let mut led = gpioa.pa1.into_push_pull_pull_output(cs);
+//!     let mut led = gpioa.pa1.into_push_pull_pull_output(&cs);
 //!
 //!     let mut timer = Timer::tim1(p.TIM1, Hertz(1), &mut rcc);
 //!     loop {
diff --git a/src/usb.rs b/src/usb.rs
index ba5e792..828b900 100644
--- a/src/usb.rs
+++ b/src/usb.rs
@@ -30,7 +30,7 @@ unsafe impl UsbPeripheral for Peripheral {
     fn enable() {
         let rcc = unsafe { &*RCC::ptr() };
 
-        cortex_m::interrupt::free(|_| {
+        critical_section::with(|_| {
             // Enable USB peripheral
             rcc.apb1enr.modify(|_, w| w.usben().set_bit());