From f25beac361f2032c3c8fab4185a8472baae36d70 Mon Sep 17 00:00:00 2001
From: iceman1001 <iceman@iuse.se>
Date: Fri, 17 Jan 2020 14:25:57 +0100
Subject: [PATCH] less checks in time critical loops

---
 armsrc/lfadc.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/armsrc/lfadc.c b/armsrc/lfadc.c
index c715020a2..eaaa38631 100644
--- a/armsrc/lfadc.c
+++ b/armsrc/lfadc.c
@@ -22,7 +22,7 @@
 // as a counting signal. TIMER_CLOCK3 = MCK/32, MCK is running at 48 MHz, so the timer is running at 48/32 = 1500 kHz
 // Carrier period (T0) have duration of 8 microseconds (us), which is 1/125000 per second (125 kHz frequency)
 // T0 = timer/carrier = 1500kHz/125kHz = 1500000/125000 = 6
-#define T0 3
+//#define HITAG_T0 3
 
 //////////////////////////////////////////////////////////////////////////////
 // Global variables
@@ -52,9 +52,21 @@ size_t lf_count_edge_periods_ex(size_t max, bool wait, bool detect_gap) {
     volatile uint8_t adc_val;
     //uint8_t avg_peak = 140, avg_through = 96;
     uint8_t avg_peak = 130, avg_through = 106;
+    int16_t checked = 0;
+
+    while (true) {
+
+        // only every 1000th times, in order to save time when collecting samples.
+        if (checked == 1000) {
+            if (BUTTON_PRESS() || data_available()) {
+                checked = -1;
+                break;
+            } else {
+                checked = 0;
+            }
+        }
+        ++checked;
 
-    while (!BUTTON_PRESS()) {
-        // Watchdog hit
         WDT_HIT();
 
         if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {