1 files changed, 5 insertions, 0 deletions
diff --git a/lib/README b/lib/README
index d81afc12..38eaadb2 100644
--- a/lib/README
+++ b/lib/README
@@ -18,6 +18,11 @@ Atmel.SAM3X_DFP.1.0.50.atpack zip file found at:
 version 1.0.50 (extracted on 20180725). It has been modified to
 compile with gcc's LTO feature. See sam3x.patch for the modifications.
 
+The samd21 directory contains code from the
+Atmel.SAMD21_DFP.1.3.304.atpack zip file found at:
+  http://packs.download.atmel.com/
+version 1.3.304 (extracted on 20180725).
+
 The lpc176x directory contains code from the mbed project:
   https://github.com/ARMmbed/mbed-os
 version mbed-os-5.8.3 (c05d72c3c005fbb7e92c3994c32bda45218ae7fe).