From a0afdcf476ff9157c29b3e2fcd9594cac329e1f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A1szl=C3=B3=20Monda?= <laci@monda.hu>
Date: Tue, 14 Nov 2017 22:54:53 +0100
Subject: [PATCH] Implement key debouncer.

---
 right/src/init_peripherals.c   |  2 ++
 right/src/key_debouncer.c      | 32 ++++++++++++++++++++++++++++++++
 right/src/key_debouncer.h      | 18 ++++++++++++++++++
 right/src/key_scanner.h        |  2 +-
 right/src/key_states.h         |  1 +
 right/src/peripherals/pit.h    | 26 +++++++++++++++++---------
 right/src/usb_report_updater.c |  8 ++++++++
 7 files changed, 79 insertions(+), 10 deletions(-)
 create mode 100644 right/src/key_debouncer.c
 create mode 100644 right/src/key_debouncer.h

diff --git a/right/src/init_peripherals.c b/right/src/init_peripherals.c
index bd84feb..53e1d16 100644
--- a/right/src/init_peripherals.c
+++ b/right/src/init_peripherals.c
@@ -14,6 +14,7 @@
 #include "eeprom.h"
 #include "microseconds/microseconds_pit.c"
 #include "timer.h"
+#include "key_debouncer.h"
 
 void InitInterruptPriorities(void)
 {
@@ -122,6 +123,7 @@ void InitPeripherals(void)
 #ifdef I2C_WATCHDOG
     InitI2cWatchdog();
 #endif
+    InitKeyDebouncer();
     EEPROM_Init();
     //microseconds_init();
 }
diff --git a/right/src/key_debouncer.c b/right/src/key_debouncer.c
new file mode 100644
index 0000000..8a85eb3
--- /dev/null
+++ b/right/src/key_debouncer.c
@@ -0,0 +1,32 @@
+#include "key_debouncer.h"
+#include "fsl_pit.h"
+#include "slot.h"
+#include "module.h"
+#include "key_states.h"
+#include "peripherals/test_led.h"
+
+void PIT_KEY_DEBOUNCER_HANDLER(void)
+{
+    TEST_LED_TOGGLE();
+    for (uint8_t slotId=0; slotId<SLOT_COUNT; slotId++) {
+        for (uint8_t keyId=0; keyId<MAX_KEY_COUNT_PER_MODULE; keyId++) {
+            uint8_t *debounceCounter = &KeyStates[slotId][keyId].debounceCounter;
+            if (*debounceCounter < 0xff) {
+                (*debounceCounter)++;
+            }
+        }
+    }
+
+    PIT_ClearStatusFlags(PIT, PIT_KEY_DEBOUNCER_CHANNEL, PIT_TFLG_TIF_MASK);
+}
+
+void InitKeyDebouncer(void)
+{
+    pit_config_t pitConfig;
+    PIT_GetDefaultConfig(&pitConfig);
+    PIT_Init(PIT, &pitConfig);
+    PIT_SetTimerPeriod(PIT, PIT_KEY_DEBOUNCER_CHANNEL, MSEC_TO_COUNT(KEY_DEBOUNCER_INTERVAL_MSEC, PIT_SOURCE_CLOCK));
+    PIT_EnableInterrupts(PIT, PIT_KEY_DEBOUNCER_CHANNEL, kPIT_TimerInterruptEnable);
+    EnableIRQ(PIT_KEY_DEBOUNCER_IRQ_ID);
+    PIT_StartTimer(PIT, PIT_KEY_DEBOUNCER_CHANNEL);
+}
diff --git a/right/src/key_debouncer.h b/right/src/key_debouncer.h
new file mode 100644
index 0000000..e83b04e
--- /dev/null
+++ b/right/src/key_debouncer.h
@@ -0,0 +1,18 @@
+#ifndef __KEY_DEBOUNCER_H__
+#define __KEY_DEBOUNCER_H__
+
+// Includes:
+
+    #include "peripherals/pit.h"
+    #include "fsl_common.h"
+
+// Macros:
+
+    #define KEY_DEBOUNCER_INTERVAL_MSEC 1
+    #define KEY_DEBOUNCER_TIMEOUT_MSEC 10
+
+// Functions:
+
+    void InitKeyDebouncer(void);
+
+#endif
diff --git a/right/src/key_scanner.h b/right/src/key_scanner.h
index f9d10d7..0a4688b 100644
--- a/right/src/key_scanner.h
+++ b/right/src/key_scanner.h
@@ -1,5 +1,5 @@
 #ifndef __KEY_SCANNER_H__
-#define __TIMER_H__
+#define __KEY_SCANNER_H__
 
 // Includes:
 
diff --git a/right/src/key_states.h b/right/src/key_states.h
index 5ad3515..847aa24 100644
--- a/right/src/key_states.h
+++ b/right/src/key_states.h
@@ -13,6 +13,7 @@
         bool previous;
         bool current;
         bool suppressed;
+        uint8_t debounceCounter;
     } key_state_t;
 
 // Variables:
diff --git a/right/src/peripherals/pit.h b/right/src/peripherals/pit.h
index 13389dc..530c805 100644
--- a/right/src/peripherals/pit.h
+++ b/right/src/peripherals/pit.h
@@ -1,20 +1,28 @@
 #ifndef __PIT_H__
 #define __PIT_H__
 
+// Includes:
+
+    #include "peripherals/pit.h"
+
 // Macros:
 
     #define PIT_SOURCE_CLOCK CLOCK_GetFreq(kCLOCK_BusClk)
 
-    #define PIT_I2C_WATCHDOG_HANDLER PIT0_IRQHandler
-    #define PIT_I2C_WATCHDOG_IRQ_ID  PIT0_IRQn
-    #define PIT_I2C_WATCHDOG_CHANNEL kPIT_Chnl_0
+    #define PIT_I2C_WATCHDOG_HANDLER  PIT0_IRQHandler
+    #define PIT_I2C_WATCHDOG_IRQ_ID   PIT0_IRQn
+    #define PIT_I2C_WATCHDOG_CHANNEL  kPIT_Chnl_0
 
-    #define PIT_TIMER_HANDLER        PIT1_IRQHandler
-    #define PIT_TIMER_IRQ_ID         PIT1_IRQn
-    #define PIT_TIMER_CHANNEL        kPIT_Chnl_1
+    #define PIT_TIMER_HANDLER         PIT1_IRQHandler
+    #define PIT_TIMER_IRQ_ID          PIT1_IRQn
+    #define PIT_TIMER_CHANNEL         kPIT_Chnl_1
 
-    #define PIT_KEY_SCANNER_HANDLER  PIT2_IRQHandler
-    #define PIT_KEY_SCANNER_IRQ_ID   PIT2_IRQn
-    #define PIT_KEY_SCANNER_CHANNEL  kPIT_Chnl_2
+    #define PIT_KEY_SCANNER_HANDLER   PIT2_IRQHandler
+    #define PIT_KEY_SCANNER_IRQ_ID    PIT2_IRQn
+    #define PIT_KEY_SCANNER_CHANNEL   kPIT_Chnl_2
+
+    #define PIT_KEY_DEBOUNCER_HANDLER PIT3_IRQHandler
+    #define PIT_KEY_DEBOUNCER_IRQ_ID  PIT3_IRQn
+    #define PIT_KEY_DEBOUNCER_CHANNEL kPIT_Chnl_3
 
 #endif
diff --git a/right/src/usb_report_updater.c b/right/src/usb_report_updater.c
index f4d0c03..f248307 100644
--- a/right/src/usb_report_updater.c
+++ b/right/src/usb_report_updater.c
@@ -12,6 +12,7 @@
 #include "layer.h"
 #include "usb_report_updater.h"
 #include "timer.h"
+#include "key_debouncer.h"
 
 uint32_t UsbReportUpdateTime = 0;
 
@@ -168,6 +169,13 @@ void UpdateActiveUsbReports(void)
             key_state_t *keyState = &KeyStates[slotId][keyId];
             key_action_t *action = &CurrentKeymap[activeLayer][slotId][keyId];
 
+
+            if (keyState->debounceCounter < KEY_DEBOUNCER_TIMEOUT_MSEC) {
+                keyState->current = keyState->previous;
+            } else if (!keyState->previous && keyState->current) {
+                keyState->debounceCounter = 0;
+            }
+
             if (keyState->current) {
                 if (suppressKeys) {
                     keyState->suppressed = true;