diff --git a/testhal/STM32/STM32L4xx/QSPI-N25Q128/main.c b/testhal/STM32/STM32L4xx/QSPI-N25Q128/main.c
index 51abd65cd..2b4807139 100644
--- a/testhal/STM32/STM32L4xx/QSPI-N25Q128/main.c
+++ b/testhal/STM32/STM32L4xx/QSPI-N25Q128/main.c
@@ -19,6 +19,7 @@
 
 #include "m25q.h"
 
+/* 16MB device, 2 cycles delay after NCS.*/
 const QSPIConfig qspicfg1 = {
   NULL,
   STM32_DCR_FSIZE(24) | STM32_DCR_CSHT(1)