1 files changed, 18 insertions, 0 deletions
diff --git a/src/device/usbd.c b/src/device/usbd.c
index 791d533ae..f6b00563d 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -1103,6 +1103,24 @@ bool usbd_edpt_open(uint8_t rhport, tusb_desc_endpoint_t const * desc_ep)
 {
   TU_LOG2("  Open EP %02X with Size = %u\r\n", desc_ep->bEndpointAddress, desc_ep->wMaxPacketSize.size);
 
+  if (TUSB_XFER_ISOCHRONOUS == desc_ep->bmAttributes.xfer)
+  {
+    TU_ASSERT(desc_ep->wMaxPacketSize.size <= (_usbd_dev.speed == TUSB_SPEED_HIGH ? 1024 : 1023));
+  }
+  else
+  {
+    uint16_t const max_epsize = (_usbd_dev.speed == TUSB_SPEED_HIGH ? 512 : 64);
+
+    if (TUSB_XFER_BULK == desc_ep->bmAttributes.xfer)
+    {
+      // Bulk must be EXACTLY 512/64 bytes
+      TU_ASSERT(desc_ep->wMaxPacketSize.size == max_epsize);
+    }else
+    {
+      TU_ASSERT(desc_ep->wMaxPacketSize.size <= max_epsize);
+    }
+  }
+
   return dcd_edpt_open(rhport, desc_ep);
 }