diff --git a/snippets/test1/test1.c b/snippets/test1/test1.c
index de0fb32..f89c022 100644
--- a/snippets/test1/test1.c
+++ b/snippets/test1/test1.c
@@ -60,6 +60,7 @@ const uint8_t MDR1_F_BW  = 0b01000000;
 const uint8_t MDR1_F_CY  = 0b10000000;
 
 
+volatile uint32_t ec = 0;
 volatile uint32_t savedCounter = 0;
 uint32_t lastSavedCounter = 0;
 
@@ -93,6 +94,7 @@ uint32_t read32(uint8_t c) {
 
 void isr() {
   savedCounter = read32(CMD_RD | REG_OTR);
+  ec++;
 }
 
 void init() {
@@ -120,7 +122,7 @@ int main (void) {
   while (1) {
     uint32_t diff = savedCounter - lastSavedCounter;
     lastSavedCounter = savedCounter;
-    printf("%d\n", diff);
+    printf("%d %d\n", ec, diff);
 
     sleep(1);
   }