From 73d36ebb6b9d7291fdb43592b271dd8b161ccad9 Mon Sep 17 00:00:00 2001
From: thomas-ha <thomas-ha@users.noreply.github.com>
Date: Mon, 7 Mar 2016 18:34:54 +0100
Subject: [PATCH] SFD timestamp

Only save SFD timestamp when we are actually receiving.
---
 cpu/cc2538/dev/cc2538-rf.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/cpu/cc2538/dev/cc2538-rf.c b/cpu/cc2538/dev/cc2538-rf.c
index a76c1c356..fda88ceed 100644
--- a/cpu/cc2538/dev/cc2538-rf.c
+++ b/cpu/cc2538/dev/cc2538-rf.c
@@ -1075,7 +1075,9 @@ cc2538_rf_rx_tx_isr(void)
   
 #if CC2538_RF_CONF_SFD_TIMESTAMPS
   if(poll_mode) {
-    cc2538_sfd_rtime = RTIMER_NOW();
+    if(REG(RFCORE_XREG_FSMSTAT1) & RFCORE_XREG_FSMSTAT1_RX_ACTIVE) {
+      cc2538_sfd_rtime = RTIMER_NOW();
+    }
   }
 #endif