From f4a7c85c1ab8e8489610c3ffc31cc2db1ed709c3 Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@helsinki.at>
Date: Mon, 2 Jun 2014 14:37:14 +0000
Subject: added LP filter for GPIO Input


diff --git a/software/rhmixxx/gpio.c b/software/rhmixxx/gpio.c
index bd4906a..dcba880 100644
--- a/software/rhmixxx/gpio.c
+++ b/software/rhmixxx/gpio.c
@@ -27,7 +27,12 @@
 #define GPIO_PORT PORTE
 #define GPIO_DDR DDRE
 
-uint8_t input_last_sent[GPIO_NUM_INPUTS];
+#define GPIO_INPUT_LP_CNT_MAX 200
+static struct {
+  uint8_t last_sent;
+  int16_t lp_cnt;
+} gpio_input_state[GPIO_NUM_INPUTS];
+
 
 void gpio_init(void)
 {
@@ -35,8 +40,10 @@ void gpio_init(void)
   GPIO_PORT = 0xF0;
 
   uint8_t i;
-  for(i = 0; i < GPIO_NUM_INPUTS; ++i)
-    input_last_sent[i] = 0;
+  for(i = 0; i < GPIO_NUM_INPUTS; ++i) {
+    gpio_input_state[i].last_sent = 0;
+    gpio_input_state[i].lp_cnt = 0;
+  }
 }
 
 void gpio_out_on(uint8_t num)
@@ -68,9 +75,16 @@ void gpio_task(void)
   uint8_t i;
   for(i = 0; i < GPIO_NUM_INPUTS; ++i) {
     uint8_t current_state = GPIO_PIN & (1<<(i+4));
-    if(current_state != input_last_sent[i]) {
-      input_last_sent[i] = current_state;
-      eventqueue_push(i + GPIO_MIDI_NOTE_OFFSET, ((current_state) ? 0 : 1));
+
+    gpio_input_state[i].lp_cnt += current_state ? -1 : +1;
+    if(gpio_input_state[i].lp_cnt <= 0 ||
+       gpio_input_state[i].lp_cnt >= GPIO_INPUT_LP_CNT_MAX) {
+
+      gpio_input_state[i].lp_cnt = gpio_input_state[i].lp_cnt <= 0 ? 0 : GPIO_INPUT_LP_CNT_MAX;
+      if(current_state != gpio_input_state[i].last_sent) {
+        gpio_input_state[i].last_sent = current_state;
+        eventqueue_push(GPIO_MIDI_NOTE_OFFSET + i, ((current_state) ? 0 : 1));
+      }
     }
   }
 }
-- 
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