From 97296db236e83a17a12608afe66667b085a1376f Mon Sep 17 00:00:00 2001
From: Ken <>
Date: Wed, 30 Oct 2019 14:33:15 -0400
Subject: [PATCH 1/2] Finish implementing digitalWriteFast to save MCU cycles.

Moved Serial.begin to be after the call to attachInterrupt for code clarity.
---
 .../src/Pyr0_Piezo_Sensor_V2.x.x.cpp                 | 12 ++++++------
 .../Pyr0_Piezo_Sensor_v2.x.x/src/pP_function.h       | 12 ++++++------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/Pyr0_Piezo_Sensor_V2.x.x.cpp b/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/Pyr0_Piezo_Sensor_V2.x.x.cpp
index 04bc410..af37f29 100644
--- a/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/Pyr0_Piezo_Sensor_V2.x.x.cpp
+++ b/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/Pyr0_Piezo_Sensor_V2.x.x.cpp
@@ -119,10 +119,10 @@ void setup() {
   pinMode(GADJ_R1, INPUT);        // declare input to set high impedance
   pinMode(GADJ_R2, INPUT);        // declare input to set high impedance
   pinMode(GADJ_R3, INPUT);        // declare input to set high impedance
-  Serial.begin(9600);
 
   attachInterrupt(digitalPinToInterrupt(Z_TRG), pulse, FALLING);
 
+  Serial.begin(9600);
   Serial.println("Initializing Pyr0-Piezo Sensor...");
 
   restoreConfig();
@@ -138,8 +138,8 @@ void loop() {
     // Blink LED's on init
     if (BlinkCount > 0) {
       BlinkState = !BlinkState;
-      digitalWrite(ERR_LED, BlinkState);
-      digitalWrite(TRG_OUT, BlinkState);
+      digitalWriteFast(ERR_LED, BlinkState);
+      digitalWriteFast(TRG_OUT, BlinkState);
       --BlinkCount;
     }
 
@@ -174,8 +174,8 @@ void loop() {
     // Blink LED's on init
     if (BlinkCount > 0) {
       BlinkState = !BlinkState;
-      digitalWrite(ERR_LED, BlinkState);
-      digitalWrite(TRG_OUT, BlinkState);
+      digitalWriteFast(ERR_LED, BlinkState);
+      digitalWriteFast(TRG_OUT, BlinkState);
       --BlinkCount;
     } else {
       // Check for error state
@@ -187,7 +187,7 @@ void loop() {
       serialPrintState();
     }
     // Sets trigger output state to false after completing loop
-    //digitalWrite(TRG_OUT, HIGH);
+    //digitalWriteFast(TRG_OUT, HIGH);
     sensorHReading = 0;
   }
 }
diff --git a/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_function.h b/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_function.h
index f10701e..fdf588f 100644
--- a/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_function.h
+++ b/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_function.h
@@ -120,25 +120,25 @@ void adjustGain() {
   }
   else if (GAIN_FACTOR > 0) {
     pinMode(GADJ_R3, OUTPUT);
-    digitalWrite(GADJ_R3, LOW);
+    digitalWriteFast(GADJ_R3, LOW);
     pinMode(GADJ_R2, INPUT);
     pinMode(GADJ_R1, INPUT);
     pinMode(GADJ_R0, INPUT);
   }
   else if (GAIN_FACTOR > 1) {
     pinMode(GADJ_R2, OUTPUT);
-    digitalWrite(GADJ_R2, LOW);
+    digitalWriteFast(GADJ_R2, LOW);
     pinMode(GADJ_R1, INPUT);
     pinMode(GADJ_R0, INPUT);
   }
   else if (GAIN_FACTOR > 2) {
     pinMode(GADJ_R1, OUTPUT);
-    digitalWrite(GADJ_R1, LOW);
+    digitalWriteFast(GADJ_R1, LOW);
     pinMode(GADJ_R0, INPUT);
   }
   else if (GAIN_FACTOR > 3) {
     pinMode(GADJ_R0, OUTPUT);
-    digitalWrite(GADJ_R0, LOW);
+    digitalWriteFast(GADJ_R0, LOW);
   }
 }
 
@@ -146,11 +146,11 @@ void adjustGain() {
 
 void checkError () {
   if (ERR_STATE == 1) {
-    digitalWrite(ERR_LED, BlinkState);
+    digitalWriteFast(ERR_LED, BlinkState);
     BlinkState = !BlinkState;
   }
   else if (ERR_STATE == 0) {
     BlinkState = LOW;
-    digitalWrite(ERR_LED, BlinkState);
+    digitalWriteFast(ERR_LED, BlinkState);
   }
 }

From eb052133a3e8ff98adfc93e52984e0c1b626b0d0 Mon Sep 17 00:00:00 2001
From: Ken <>
Date: Wed, 30 Oct 2019 15:42:45 -0400
Subject: [PATCH 2/2] =?UTF-8?q?Code=20change=20implements=20analogReadFast?=
 =?UTF-8?q?,=20which=20reduces=20the=20read=20time=20of=20an=20anolog=20pi?=
 =?UTF-8?q?n=20from=20112=20=C2=B5S=20down=20to=2021=20=C2=B5S.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../src/Pyr0_Piezo_Sensor_V2.x.x.cpp                      | 4 ++--
 .../AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_function.h | 8 ++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/Pyr0_Piezo_Sensor_V2.x.x.cpp b/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/Pyr0_Piezo_Sensor_V2.x.x.cpp
index af37f29..26bddca 100644
--- a/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/Pyr0_Piezo_Sensor_V2.x.x.cpp
+++ b/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/Pyr0_Piezo_Sensor_V2.x.x.cpp
@@ -156,8 +156,8 @@ void loop() {
 
     // Check voltage of first and second stages and compare against thresholds
     readVin();
-    VComp = analogRead(VCOMP_SENSE_PIN);
-    VFol = analogRead(V_FOLLOW_PIN);
+    VComp = analogReadFast(VCOMP_SENSE_PIN);
+    VFol = analogReadFast(V_FOLLOW_PIN);
 
     VLast = VOld - Vin;
     if (VLast > Hyst || VLast < -Hyst) {
diff --git a/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_function.h b/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_function.h
index fdf588f..4395428 100644
--- a/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_function.h
+++ b/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_function.h
@@ -12,6 +12,14 @@ void digitalWriteFast(uint8_t pin, uint8_t x) {
   }
 }
 
+int inline analogReadFast(byte ADCpin)
+{ byte ADCSRAoriginal = ADCSRA;
+  ADCSRA = (ADCSRA & B11111000) | 4;
+  int adc = analogRead(ADCpin);
+  ADCSRA = ADCSRAoriginal;
+  return adc;
+}
+
 /*------------------------------------------------*/
 
 void pulse() {