diff --git a/src/bus/four_wire.rs b/src/bus/four_wire.rs
index a55c55f..f33f5d5 100644
--- a/src/bus/four_wire.rs
+++ b/src/bus/four_wire.rs
@@ -9,6 +9,8 @@ use crate::bus::Bus;
 const WRITE_MODE_MASK: u8 = 0b00000_1_00;
 
 // TODO This name is not ideal, should be renamed to VDM
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct FourWire<Spi: Transfer<u8> + Write<u8>, ChipSelect: OutputPin> {
     cs: ChipSelect,
     spi: Spi,
diff --git a/src/bus/four_wire_ref.rs b/src/bus/four_wire_ref.rs
index af3265b..0a653a5 100644
--- a/src/bus/four_wire_ref.rs
+++ b/src/bus/four_wire_ref.rs
@@ -9,6 +9,8 @@ use crate::bus::{Bus, FourWire, FourWireError};
 // TODO This name is not ideal, should be renamed to VDM
 /// This is just like [crate::bus::FourWire] but takes references instead of ownership
 /// for the SPI bus and the ChipSelect pin
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct FourWireRef<'a, Spi: Transfer<u8> + Write<u8>, ChipSelect: OutputPin>(
     FourWire<SpiRef<'a, Spi>, OutputPinRef<'a, ChipSelect>>,
 );
@@ -43,6 +45,7 @@ impl<Spi: Transfer<u8> + Write<u8>, ChipSelect: OutputPin> Bus
 }
 
 #[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct SpiRef<'a, Spi: Transfer<u8> + Write<u8>>(pub &'a mut Spi);
 
 impl<'a, Spi: Transfer<u8> + Write<u8>> Transfer<u8> for SpiRef<'a, Spi> {
@@ -64,6 +67,7 @@ impl<'a, Spi: Transfer<u8> + Write<u8>> Write<u8> for SpiRef<'a, Spi> {
 }
 
 #[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct OutputPinRef<'a, P: OutputPin>(pub &'a mut P);
 
 impl<'a, P: OutputPin> OutputPin for OutputPinRef<'a, P> {
diff --git a/src/bus/three_wire.rs b/src/bus/three_wire.rs
index fe55615..1a21f82 100644
--- a/src/bus/three_wire.rs
+++ b/src/bus/three_wire.rs
@@ -12,6 +12,8 @@ const FIXED_DATA_LENGTH_MODE_2: u8 = 0b000000_10;
 const FIXED_DATA_LENGTH_MODE_4: u8 = 0b000000_11;
 
 // TODO This name is not ideal, should be renamed to FDM
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct ThreeWire<Spi: Transfer<u8> + Write<u8>> {
     spi: Spi,
 }
diff --git a/src/device.rs b/src/device.rs
index 107a600..bf41a7c 100644
--- a/src/device.rs
+++ b/src/device.rs
@@ -19,6 +19,8 @@ impl<E> From<E> for ResetError<E> {
     }
 }
 
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub(crate) struct DeviceState<HostImpl: Host> {
     host: HostImpl,
     sockets: [u8; 1],
@@ -104,6 +106,8 @@ impl<SpiBus: Bus, HostImpl: Host> Device<SpiBus, HostImpl> {
     }
 }
 
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct InactiveDevice<HostImpl: Host>(DeviceState<HostImpl>);
 
 impl<HostImpl: Host> InactiveDevice<HostImpl> {
diff --git a/src/host/dhcp.rs b/src/host/dhcp.rs
index 521a831..b8a933b 100644
--- a/src/host/dhcp.rs
+++ b/src/host/dhcp.rs
@@ -2,6 +2,8 @@ use crate::bus::Bus;
 use crate::host::Host;
 use crate::MacAddress;
 
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct Dhcp {
     // settings: HostConfig,
     // current: HostConfig,
diff --git a/src/host/manual.rs b/src/host/manual.rs
index 0f61022..5b0b32c 100644
--- a/src/host/manual.rs
+++ b/src/host/manual.rs
@@ -3,6 +3,8 @@ use crate::host::{Host, HostConfig};
 use crate::MacAddress;
 use embedded_nal::Ipv4Addr;
 
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct Manual {
     is_setup: bool,
     settings: HostConfig,
diff --git a/src/host/mod.rs b/src/host/mod.rs
index 206ec91..8aa1b79 100644
--- a/src/host/mod.rs
+++ b/src/host/mod.rs
@@ -8,10 +8,15 @@ use crate::register;
 use crate::MacAddress;
 use embedded_nal::Ipv4Addr;
 
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct HostConfig {
     mac: MacAddress,
+    #[cfg_attr(feature = "defmt", defmt(Display2Format))]
     ip: Ipv4Addr,
+    #[cfg_attr(feature = "defmt", defmt(Display2Format))]
     gateway: Ipv4Addr,
+    #[cfg_attr(feature = "defmt", defmt(Display2Format))]
     subnet: Ipv4Addr,
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index ac237a7..cbe9761 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,7 +22,8 @@ pub use uninitialized_device::UninitializedDevice;
 
 /// Settings for wake on LAN.  Allows the W5500 to optionally emit an interrupt upon receiving a packet
 #[repr(u8)]
-#[derive(Copy, Clone, PartialOrd, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialOrd, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum OnWakeOnLan {
     InvokeInterrupt = 0b00100000,
     Ignore = 0b00000000,
@@ -30,7 +31,8 @@ pub enum OnWakeOnLan {
 
 /// Settings for ping.  Allows the W5500 to respond to or ignore network ping requests
 #[repr(u8)]
-#[derive(Copy, Clone, PartialOrd, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialOrd, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum OnPingRequest {
     Respond = 0b00000000,
     Ignore = 0b00010000,
@@ -39,20 +41,23 @@ pub enum OnPingRequest {
 /// Use [ConnectionType::PPoE] when talking
 /// to an ADSL modem. Otherwise use [ConnectionType::Ethernet]
 #[repr(u8)]
-#[derive(Copy, Clone, PartialOrd, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialOrd, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum ConnectionType {
     PPoE = 0b00001000,
     Ethernet = 0b00000000,
 }
 
-#[derive(Copy, Clone, PartialOrd, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialOrd, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(u8)]
 pub enum ArpResponses {
     Cache = 0b00000000,
     DropAfterUse = 0b00000010,
 }
 
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct Mode {
     pub on_wake_on_lan: OnWakeOnLan,
     pub on_ping_request: OnPingRequest,
diff --git a/src/net.rs b/src/net.rs
index c77cef2..b504bdd 100644
--- a/src/net.rs
+++ b/src/net.rs
@@ -18,6 +18,7 @@ pub use embedded_nal::Ipv4Addr;
 ///
 /// This is an EUI-48 MAC address (previously called MAC-48).
 #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Debug, Hash, Default)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct MacAddress {
     /// Octets of the MAC address.
     pub octets: [u8; 6],
diff --git a/src/raw_device.rs b/src/raw_device.rs
index fe80a6d..25413fc 100644
--- a/src/raw_device.rs
+++ b/src/raw_device.rs
@@ -1,6 +1,8 @@
 use crate::{bus::Bus, register, socket::Socket, uninitialized_device::InitializeError};
 
 /// The W5500 operating in MACRAW mode to send and receive ethernet frames.
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct RawDevice<SpiBus: Bus> {
     bus: SpiBus,
     raw_socket: Socket,
diff --git a/src/tcp.rs b/src/tcp.rs
index 99ecc11..14e7c57 100644
--- a/src/tcp.rs
+++ b/src/tcp.rs
@@ -11,11 +11,12 @@ use embedded_nal::{nb, IpAddr, Ipv4Addr, SocketAddr, SocketAddrV4, TcpClientStac
 use core::convert::TryFrom;
 
 #[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum TcpSocketError<E: core::fmt::Debug> {
     NoMoreSockets,
     NotReady,
     UnsupportedAddress,
-    Other(E),
+    Other(#[cfg_attr(feature = "defmt", defmt(Debug2Format))] E),
     UnsupportedMode,
 }
 
@@ -25,6 +26,8 @@ impl<E: core::fmt::Debug> From<E> for TcpSocketError<E> {
     }
 }
 
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct TcpSocket {
     socket: Socket,
 }
diff --git a/src/uninitialized_device.rs b/src/uninitialized_device.rs
index 30c7975..ae230a3 100644
--- a/src/uninitialized_device.rs
+++ b/src/uninitialized_device.rs
@@ -9,6 +9,8 @@ use crate::raw_device::RawDevice;
 use crate::register;
 use crate::{MacAddress, Mode};
 
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct UninitializedDevice<SpiBus: Bus> {
     bus: SpiBus,
 }