diff --git a/src/afe.rs b/src/afe.rs
new file mode 100644
index 0000000..9238393
--- /dev/null
+++ b/src/afe.rs
@@ -0,0 +1,71 @@
+use embedded_hal;
+
+#[derive(Copy, Clone, Debug)]
+pub enum Gain {
+    G1 = 0b00,
+    G2 = 0b01,
+    G5 = 0b10,
+    G10 = 0b11
+}
+
+pub struct ProgrammableGainAmplifier<A0, A1> {
+    a0: A0,
+    a1: A1
+}
+
+impl<A0, A1> ProgrammableGainAmplifier<A0, A1>
+where
+    A0: embedded_hal::digital::v2::StatefulOutputPin,
+    A0::Error: core::fmt::Debug,
+    A1: embedded_hal::digital::v2::StatefulOutputPin,
+    A1::Error: core::fmt::Debug,
+{
+    pub fn new(a0: A0, a1: A1) -> Self
+    {
+        let mut afe = Self { a0: a0, a1: a1};
+
+        afe.set_gain(Gain::G1);
+
+        afe
+    }
+
+    pub fn set_gain(&mut self, gain: Gain) {
+        match gain {
+            Gain::G1 => {
+                self.a0.set_low().unwrap();
+                self.a1.set_low().unwrap();
+            },
+            Gain::G2 => {
+                self.a0.set_high().unwrap();
+                self.a1.set_low().unwrap();
+            },
+            Gain::G5 => {
+                self.a0.set_low().unwrap();
+                self.a1.set_high().unwrap();
+            },
+            Gain::G10 => {
+                self.a0.set_high().unwrap();
+                self.a1.set_high().unwrap();
+            },
+        }
+    }
+
+    pub fn get_gain(&self) -> Gain {
+        let lsb_set = self.a0.is_set_high().unwrap();
+        let msb_set = self.a1.is_set_high().unwrap();
+
+        if msb_set {
+            if lsb_set {
+               Gain::G10
+            } else {
+                Gain::G5
+            }
+        } else {
+            if lsb_set {
+                Gain::G2
+            } else {
+                Gain::G1
+            }
+        }
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 3da7786..d67ed37 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -53,6 +53,7 @@ static mut DES_RING: ethernet::DesRing = ethernet::DesRing::new();
 mod eth;
 mod pounder;
 mod server;
+mod afe;
 
 mod iir;
 use iir::*;
@@ -102,14 +103,24 @@ const SCALE: f32 = ((1 << 15) - 1) as f32;
 const TCP_RX_BUFFER_SIZE: usize = 8192;
 const TCP_TX_BUFFER_SIZE: usize = 8192;
 
+type AFE1 = afe::ProgrammableGainAmplifier<
+    hal::gpio::gpiof::PF2<hal::gpio::Output<hal::gpio::PushPull>>,
+    hal::gpio::gpiof::PF5<hal::gpio::Output<hal::gpio::PushPull>>>;
+
+type AFE2 = afe::ProgrammableGainAmplifier<
+    hal::gpio::gpiod::PD14<hal::gpio::Output<hal::gpio::PushPull>>,
+    hal::gpio::gpiod::PD15<hal::gpio::Output<hal::gpio::PushPull>>>;
+
 #[rtfm::app(device = stm32h7xx_hal::stm32, peripherals = true, monotonic = rtfm::cyccnt::CYCCNT)]
 const APP: () = {
     struct Resources {
         adc1: hal::spi::Spi<hal::stm32::SPI2>,
         dac1: hal::spi::Spi<hal::stm32::SPI4>,
+        _afe1: AFE1,
 
         adc2: hal::spi::Spi<hal::stm32::SPI3>,
         dac2: hal::spi::Spi<hal::stm32::SPI5>,
+        _afe2: AFE2,
 
         eeprom_i2c: hal::i2c::I2c<hal::stm32::I2C2>,
 
@@ -163,6 +174,18 @@ const APP: () = {
         let gpiof = dp.GPIOF.split(&mut clocks.ahb4);
         let gpiog = dp.GPIOG.split(&mut clocks.ahb4);
 
+        let afe1 = {
+            let a0_pin = gpiof.pf2.into_push_pull_output();
+            let a1_pin = gpiof.pf5.into_push_pull_output();
+            afe::ProgrammableGainAmplifier::new(a0_pin, a1_pin)
+        };
+
+        let afe2 = {
+            let a0_pin = gpiod.pd14.into_push_pull_output();
+            let a1_pin = gpiod.pd15.into_push_pull_output();
+            afe::ProgrammableGainAmplifier::new(a0_pin, a1_pin)
+        };
+
         // Configure the SPI interfaces to the ADCs and DACs.
         let adc1_spi = {
             let spi_miso = gpiob.pb14.into_alternate_af5().set_speed(hal::gpio::Speed::VeryHigh);
@@ -398,6 +421,8 @@ const APP: () = {
             dac1: dac1_spi,
             adc2: adc2_spi,
             dac2: dac2_spi,
+            _afe1: afe1,
+            _afe2: afe2,
 
             dbg_pin: debug_pin,
             dac_pin: dac_pin,