diff --git a/fw16-epd-gui/src/element/button.rs b/eepy-gui/src/element/button.rs
similarity index 99%
rename from fw16-epd-gui/src/element/button.rs
rename to eepy-gui/src/element/button.rs
index 0ae87d8..ff85d15 100644
--- a/fw16-epd-gui/src/element/button.rs
+++ b/eepy-gui/src/element/button.rs
@@ -4,7 +4,7 @@ use embedded_graphics::pixelcolor::BinaryColor;
 use embedded_graphics::primitives::{CornerRadii, PrimitiveStyle, Rectangle, RoundedRectangle};
 use embedded_graphics::text::{Alignment, Baseline, Text, TextStyle, TextStyleBuilder};
 use embedded_graphics::text::renderer::TextRenderer;
-use fw16_epd_program_interface::{Event, TouchEventType};
+use eepy_sys::{Event, TouchEventType};
 use crate::draw_target::EpdDrawTarget;
 use crate::element::{Gui, DEFAULT_PRIMITIVE_STYLE, DEFAULT_TEXT_STYLE};
 
diff --git a/fw16-epd-gui/src/element/mod.rs b/eepy-gui/src/element/mod.rs
similarity index 96%
rename from fw16-epd-gui/src/element/mod.rs
rename to eepy-gui/src/element/mod.rs
index b746122..b7939e3 100644
--- a/fw16-epd-gui/src/element/mod.rs
+++ b/eepy-gui/src/element/mod.rs
@@ -6,7 +6,7 @@ use embedded_graphics::mono_font::MonoTextStyle;
 use embedded_graphics::pixelcolor::BinaryColor;
 use embedded_graphics::prelude::*;
 use embedded_graphics::primitives::{PrimitiveStyle, PrimitiveStyleBuilder, Rectangle};
-use fw16_epd_program_interface::Event;
+use eepy_sys::Event;
 use tp370pgh01::{DIM_X, DIM_Y};
 use crate::draw_target::EpdDrawTarget;
 
diff --git a/fw16-epd-gui/src/element/slider.rs b/eepy-gui/src/element/slider.rs
similarity index 98%
rename from fw16-epd-gui/src/element/slider.rs
rename to eepy-gui/src/element/slider.rs
index 61feca8..f4b60ef 100644
--- a/fw16-epd-gui/src/element/slider.rs
+++ b/eepy-gui/src/element/slider.rs
@@ -2,7 +2,7 @@ use embedded_graphics::prelude::*;
 use embedded_graphics::geometry::Point;
 use embedded_graphics::pixelcolor::BinaryColor;
 use embedded_graphics::primitives::{Circle, Line, PrimitiveStyle, Rectangle};
-use fw16_epd_program_interface::{Event, TouchEventType};
+use eepy_sys::{Event, TouchEventType};
 use crate::draw_target::EpdDrawTarget;
 use crate::element::{Gui, DEFAULT_PRIMITIVE_STYLE};
 
diff --git a/eepy-sys/src/lib.rs b/eepy-sys/src/lib.rs
index b0e3fcc..7f1a8b0 100644
--- a/eepy-sys/src/lib.rs
+++ b/eepy-sys/src/lib.rs
@@ -1,6 +1,7 @@
 #![no_std]
 
 pub mod header;
+pub mod syscall;
 
 use core::fmt::{Display, Formatter};
 pub use tp370pgh01::IMAGE_BYTES;
diff --git a/eepy-sys/src/syscall/mod.rs b/eepy-sys/src/syscall/mod.rs
new file mode 100644
index 0000000..a6bfd6d
--- /dev/null
+++ b/eepy-sys/src/syscall/mod.rs
@@ -0,0 +1,24 @@
+/// Perform a raw system call.
+#[macro_export]
+macro_rules! syscall {
+    (
+        $syscall_num:expr,
+        $( out $r0out:ident )? $( in $r0in:expr )?,
+        $( out $r1out:ident )? $( in $r1in:expr )?,
+        $( out $r2out:ident )? $( in $r2in:expr )?,
+        $( out $r3out:ident )? $( in $r3in:expr )?,
+    ) => {
+        asm!(
+            "svc #{syscall_num}",
+            $( in("r0") $r0in, )?
+            $( lateout("r0") $r0out, )?
+            $( in("r1") $r1in, )?
+            $( lateout("r1") $r1out, )?
+            $( in("r2") $r2in, )?
+            $( lateout("r2") $r2out, )?
+            $( in("r3") $r3in, )?
+            $( lateout("r3") $r3out, )?
+            syscall_num = const $syscall_num,
+        );
+    }
+}
diff --git a/eepy/src/main.rs b/eepy/src/main.rs
index 1e5c510..b5d007c 100644
--- a/eepy/src/main.rs
+++ b/eepy/src/main.rs
@@ -5,7 +5,9 @@ mod programs;
 mod gui;
 mod serial;
 mod ringbuffer;
+mod syscall;
 
+use core::arch::asm;
 #[allow(unused_imports)]
 use panic_probe as _;
 #[allow(unused_imports)]
@@ -37,7 +39,7 @@ use fw16_epd_bsp::hal::timer::{Alarm, Alarm0};
 use fw16_epd_bsp::pac::I2C0;
 use fw16_epd_bsp::pac::interrupt;
 use eepy_gui::draw_target::EpdDrawTarget;
-use eepy_sys::{Event, RefreshBlockMode, SafeOption, TouchEvent, TouchEventType};
+use eepy_sys::{syscall as do_syscall, Event, RefreshBlockMode, SafeOption, TouchEvent, TouchEventType};
 use tp370pgh01::rp2040::{Rp2040PervasiveSpiDelays, IoPin};
 use tp370pgh01::{Tp370pgh01, IMAGE_BYTES};
 use crate::ringbuffer::RingBuffer;
@@ -326,6 +328,22 @@ fn main() -> ! {
         }
     }*/
 
+    // Test syscall
+    unsafe {
+        let mut r0: usize;
+        let mut r1: usize;
+        let mut r2: usize;
+        let mut r3: usize;
+        do_syscall!(
+            31,
+            out r0 in 0,
+            out r1 in 1,
+            out r2 in 2,
+            out r3 in 3,
+        );
+        debug!("{} {} {} {}", r0, r1, r2, r3);
+    }
+
     let draw_target = EpdDrawTarget::new(write_image, refresh);
     gui::gui_main(draw_target);
 }
diff --git a/eepy/src/syscall.rs b/eepy/src/syscall.rs
new file mode 100644
index 0000000..32a8413
--- /dev/null
+++ b/eepy/src/syscall.rs
@@ -0,0 +1,28 @@
+use core::arch::{asm, global_asm};
+use cortex_m_rt::exception;
+use defmt::debug;
+
+global_asm!(include_str!("syscall.s"));
+
+/// Main syscall (SVC) handler.
+///
+/// This function is called by the assembly trampoline code in `syscall.s`.
+///
+/// `sp` contains the caller's stack pointer value (taken from either MSP or PSP depending on which
+/// stack was active). This is where the register values are pushed when the exception is triggered,
+/// so this is where we need to read/write to interface with the caller.
+/// This stack location contains (in order): r0, r1, r2, r3, r12, lr, pc, xPSR.
+/// The pc value from the stack can be used to extract the literal operand from the SVC instruction
+/// which triggered the syscall.
+#[no_mangle]
+extern "C" fn syscall(sp: *mut usize) {
+    // Stack contains R0, R1, R2, R3, R12, LR, ReturnAddress, xPSR
+    let stack_values = unsafe { core::slice::from_raw_parts_mut(sp, 8) };
+    let svc_operand = unsafe { (stack_values[6] as *const u8).sub(2).read() };
+    debug!("{:x}", svc_operand);
+
+    // Increase the value of R0-R3 by 1
+    for i in 0..4 {
+        stack_values[i] += 1;
+    }
+}
\ No newline at end of file
diff --git a/eepy/src/syscall.s b/eepy/src/syscall.s
new file mode 100644
index 0000000..c36c70f
--- /dev/null
+++ b/eepy/src/syscall.s
@@ -0,0 +1,15 @@
+.global SVCall
+.equ    SVCall, _SVCall + 1 /* thumb bit */
+
+_SVCall:
+    movs    r0, #4
+    mov     r1, lr
+    tst     r0, r1
+    beq     .use_msp
+    mrs     r0, psp
+    ldr     r1, =syscall
+    bx      r1
+.use_msp:
+    mrs     r0, msp
+    ldr     r1, =syscall
+    bx      r1
\ No newline at end of file