From 8e1b13345a6c9d3c8323001df0633b309a0e5620 Mon Sep 17 00:00:00 2001
From: Peter Cai <peter@typeblog.net>
Date: Thu, 10 Jun 2021 18:36:33 +0800
Subject: [PATCH] use a higher-precision timer implementation

---
 .gitmodules                    | 3 +++
 Makefile                       | 3 ++-
 TimerCounter                   | 1 +
 c_cpp_properties.json.template | 3 ++-
 main.cpp                       | 6 +++++-
 5 files changed, 13 insertions(+), 3 deletions(-)
 create mode 160000 TimerCounter

diff --git a/.gitmodules b/.gitmodules
index ba18018..46c31ab 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,6 @@
 [submodule "ArduinoMIDI"]
 	path = ArduinoMIDI
 	url = https://github.com/FortySevenEffects/arduino_midi_library
+[submodule "TimerCounter"]
+	path = TimerCounter
+	url = https://github.com/ElectricRCAircraftGuy/eRCaGuy_TimerCounter
diff --git a/Makefile b/Makefile
index a9909a1..d1d8474 100644
--- a/Makefile
+++ b/Makefile
@@ -24,6 +24,7 @@ VPATH       := $(foreach path, ${VPATH}, ${path} $(shell find ${path} -type d))
 # the VPATH list
 VPATH       += ${PWD} \
 	${PWD}/ArduinoMIDI/src \
+	${PWD}/TimerCounter \
 
 # Build parameters
 BUILD_DIR   := out
@@ -36,7 +37,7 @@ INCS        := \
 	$(foreach path, ${VPATH}, -I ${path}) \
 	$(foreach path, ${VARIANTS}, -I ${path}) \
 
-CFLAGS      := -O3 -DF_CPU=16000000UL ${MMCU} ${INCS}
+CFLAGS      := -O3 -DF_CPU=16000000UL -DARDUINO=1000 ${MMCU} ${INCS}
 # Generate sections for each function and variable
 # so that LD can eliminate unused functions and variables
 CFLAGS      += -ffunction-sections -fdata-sections
diff --git a/TimerCounter b/TimerCounter
new file mode 160000
index 0000000..f2651c7
--- /dev/null
+++ b/TimerCounter
@@ -0,0 +1 @@
+Subproject commit f2651c78bce8a1b5f69d707ac3d019ef17ab8055
diff --git a/c_cpp_properties.json.template b/c_cpp_properties.json.template
index 9474bf5..6a044d1 100644
--- a/c_cpp_properties.json.template
+++ b/c_cpp_properties.json.template
@@ -10,7 +10,8 @@
             ],
             "defines": [
                 "__ATmega328P__",
-                "__AVR_ATmega328P__"
+                "__AVR_ATmega328P__",
+                "ARDUINO=1000",
             ]
         }
     ]
diff --git a/main.cpp b/main.cpp
index 5a8d02c..d896d2f 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,5 +1,6 @@
 #include <Arduino.h>
 #include <MIDI.h>
+#include <eRCaGuy_Timer2_Counter.h>
 #include "motor_control.h"
 
 #define NUM_MOTORS 4
@@ -53,6 +54,9 @@ int main() {
     // Needed for some functions to work (like micros)
     init();
 
+    // Timer based on Timer 2 (this breaks PWM output)
+    timer2.setup();
+
     // Enable the motor drivers
     pinMode(8, OUTPUT);
     digitalWrite(8, LOW);
@@ -70,7 +74,7 @@ int main() {
     MIDI.setHandleNoteOff(midi_note_off);
 
     while (true) {
-        unsigned long cur_micros = micros();
+        unsigned long cur_micros = timer2.get_count() / 2ul; // The unit of get_count is 0.5us
         handle_tick(cur_micros);
         MIDI.read();
     }