diff --git a/sys/sys/ata.h b/sys/sys/ata.h
index ceffb32de6f..cb18a4a9292 100644
--- a/sys/sys/ata.h
+++ b/sys/sys/ata.h
@@ -215,6 +215,7 @@ struct ata_params {
 #define ATA_UDMA5               0x45
 #define ATA_UDMA6               0x46
 #define ATA_SA150               0x47
+#define ATA_SA300               0x48
 #define ATA_DMA_MAX             0x4f