diff --git a/bluepill-rs/src/dmx.rs b/bluepill-rs/src/dmx.rs
index 01d8400..d5cbba8 100644
--- a/bluepill-rs/src/dmx.rs
+++ b/bluepill-rs/src/dmx.rs
@@ -6,7 +6,7 @@ type TxDma = dma::TxDma<serial::Tx<pac::USART1>, dma::dma1::C4>;
 type DMXUniverse<const DMX_LEN: usize> = &'static mut [u8; DMX_LEN];
 type DMXTransfer<const DMX_LEN: usize> = dma::Transfer<dma::R, DMXUniverse<DMX_LEN>, TxDma>;
 
-pub enum DMX<const DMX_LEN: usize = 512> {
+pub enum DMX<const DMX_LEN: usize = DMX_LEN_MAX> {
     Idle(Option<TxDma>, Option<DMXUniverse<DMX_LEN>>),
     Busy(Option<DMXTransfer<DMX_LEN>>),
 }
@@ -20,6 +20,8 @@ impl<const DMX_LEN: usize> DMX<DMX_LEN> {
     where
         PINS: serial::Pins<pac::USART1>,
     {
+        assert!(DMX_LEN <= DMX_LEN_MAX);
+
         serial.reconfigure(250_000.bps(), &clocks).unwrap();
 
         Self::Idle(Some(serial.tx.with_dma(channel)), None)