first commit

.gitignore

@@ -0,0 +1,5 @@
+.pio
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch

.vscode/extensions.json

@@ -0,0 +1,10 @@
+{
+    // See http://go.microsoft.com/fwlink/?LinkId=827846
+    // for the documentation about the extensions.json format
+    "recommendations": [
+        "platformio.platformio-ide"
+    ],
+    "unwantedRecommendations": [
+        "ms-vscode.cpptools-extension-pack"
+    ]
+}

include/README

@@ -0,0 +1,37 @@
+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the convention is to give header files names that end with `.h'.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

include/serialConnector.h

@@ -0,0 +1,66 @@
+#pragma once
+#include <Arduino.h>
+
+class SerialConnector
+{
+
+private:
+    String previouSent;
+    String received;
+    String command;
+
+    void (*acknowledgeHandler)(String args);
+    void (*repeatHandler)(String args);
+    void (*calibrationBeginHandler)(String args);
+    void (*calibrationInteruptHandler)(String args);
+
+    // Convert each character of `cmd` to its hexadecimal representation
+    // and return the concatenated hex string.
+    String stringToHex(String cmd);
+
+    // Compute a numeric 'check' value from `cmd` by converting chars to
+    // their hex digits and summing/concatenating (project-specific logic).
+    // Returns an integer suitable for use as a check-bit value.
+    int stringToCheckNum(String cmd);
+
+    // Return the index of character `ch` in `str`, or -1 if not found.
+    int getCharIndex(char ch, String str);
+
+    // Parse an incoming framed message and return the command portion
+    // (everything before the first '#').
+    String getCommandFromIncomming(String incomming);
+
+    // Parse an incoming framed message and return the arguments portion
+    // (text between the first and second '#').
+    String getArgsFromIncomming(String incomming);
+
+    // Parse an incoming framed message and return the final check-bit
+    // portion (everything after the second '#').
+    String getCheckBitFromIncomming(String incomming);
+
+    // Verify that the provided `checkBit` matches the computed check for
+    // the combination of `cmd` and `args`. Returns true when valid.
+    bool verifyCheckBit(String cmd, String args, int checkBit);
+
+    // Send a repeat request to the remote side to indicate the last
+    // message should be re-sent.
+    void repeat();
+
+    // Send an acknowledgement message containing `checkBit` back to the
+    // remote side.
+    void acknowledge(int checkBit);
+
+    // After sending a command, wait for and handle any follow-up messages
+    // (repeat or acknowledgement) related to `cmd`.
+    void afterSendCheck(String cmd);
+
+public:
+    void cycle();
+
+    void onAcknowledge(void (*handler)(String args));
+    void onRepeat(void (*handler)(String args));
+    void onCalibrationBegin(void (*handler)(String args));
+    void onCalibrationInterupt(void (*handler)(String args));
+
+    void sendCommand(String cmd, String args);
+};

lib/README

@@ -0,0 +1,46 @@
+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into the executable file.
+
+The source code of each library should be placed in a separate directory
+("lib/your_library_name/[Code]").
+
+For example, see the structure of the following example libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional. for custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+Example contents of `src/main.c` using Foo and Bar:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+The PlatformIO Library Dependency Finder will find automatically dependent
+libraries by scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

platformio.ini

@@ -0,0 +1,14 @@
+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:nano_33_iot]
+platform = atmelsam
+board = nano_33_iot
+framework = arduino

src/main.cpp

@@ -0,0 +1,53 @@
+#include <Arduino.h>
+#include <serialConnector.h>
+
+SerialConnector *conn = new SerialConnector();
+void calibrationBegin(String args);
+
+void setup()
+{
+    pinMode(11, OUTPUT);
+    digitalWrite(11, HIGH);
+
+    pinMode(2, INPUT);
+    pinMode(3, INPUT);
+    pinMode(4, INPUT);
+
+    Serial.begin(9600);
+
+    // Trigered when a CAL-INT command is received
+    conn->onCalibrationInterupt(&calibrationBegin);
+}
+
+void loop()
+{
+    conn->cycle();
+
+    if (!digitalRead(2))
+    {
+        conn->sendCommand("CAL-NXT", "hdsfhdsl");
+    }
+
+    if (!digitalRead(3))
+    {
+        conn->sendCommand("CAL-INT", "dgsyy");
+    }
+
+    if (!digitalRead(4))
+    {
+        conn->sendCommand("READ", "nvcmxznm");
+    }
+
+    delay(300);
+}
+
+void calibrationBegin(String args)
+{
+    for (int i = 0; i < args.toInt(); i++)
+    {
+        digitalWrite(11, LOW);
+        delay(300);
+        digitalWrite(11, HIGH);
+        delay(300);
+    }
+}

src/serialConnector.cpp

@@ -0,0 +1,257 @@
+#include <serialConnector.h>
+
+// Main polling loop: read incoming serial frames, validate the check-bit,
+// acknowledge valid messages and dispatch handlers based on the command.
+void SerialConnector::cycle()
+{
+    if (Serial.available() > 3)
+    {
+        String raw = Serial.readStringUntil('@');
+        String cmd = getCommandFromIncomming(raw);
+        String args = getArgsFromIncomming(raw);
+
+        if (!verifyCheckBit(cmd, args, getCheckBitFromIncomming(raw).toInt()))
+        {
+            repeat();
+            return;
+        }
+
+        acknowledge(getCheckBitFromIncomming(raw).toInt());
+        if (cmd == "CAL-BGN")
+        {
+            if (calibrationBeginHandler)
+                calibrationBeginHandler(args);
+        }
+        else if (cmd == "CAL-INT")
+        {
+            if (calibrationInteruptHandler)
+                calibrationInteruptHandler(args);
+        }
+        else
+        {
+        }
+    }
+}
+
+// Convert each character in `cmd` into its ASCII hexadecimal representation
+// and return the concatenated hex string. Example: "A" -> "41".
+String SerialConnector::stringToHex(String cmd)
+{
+    int hex_dec;
+    String output = "";
+
+    for (const auto &item : cmd)
+    {
+
+        hex_dec = int(item);
+        char hexaDeciNum[100];
+        int i = 0;
+
+        while (hex_dec != 0)
+        {
+            int temp = 0;
+            temp = hex_dec % 16;
+            if (temp < 10)
+            {
+                hexaDeciNum[i] = temp + 48;
+                i++;
+            }
+            else
+            {
+                hexaDeciNum[i] = temp + 55;
+                i++;
+            }
+            hex_dec = hex_dec / 16;
+        }
+        for (int j = i - 1; j >= 0; j--)
+        {
+            output += hexaDeciNum[j];
+        }
+    }
+
+    return output;
+}
+
+// Produce a numeric check value for `cmd` by converting characters to
+// their hexadecimal digits and summing their digit characters into an
+// integer representation. This mirrors the protocol used for check-bits.
+int SerialConnector::stringToCheckNum(String cmd)
+{
+    int hex_dec;
+    int output = 0;
+
+    for (const auto &item : cmd)
+    {
+
+        hex_dec = int(item);
+        char hexaDeciNum[100];
+        int i = 0;
+
+        while (hex_dec != 0)
+        {
+            int temp = 0;
+            temp = hex_dec % 16;
+            if (temp < 10)
+            {
+                hexaDeciNum[i] = temp + 48;
+                i++;
+            }
+            else
+            {
+                hexaDeciNum[i] = temp + 55;
+                i++;
+            }
+            hex_dec = hex_dec / 16;
+        }
+        for (int j = i - 1; j >= 0; j--)
+        {
+            output += hexaDeciNum[j];
+        }
+    }
+
+    return output;
+}
+
+// Return the index of `ch` inside `str`. Returns -1 if `ch` is not found.
+int SerialConnector::getCharIndex(char ch, String str)
+{
+    for (int i = 0; i < str.length(); i++)
+    {
+        if (str.charAt(i) == ch)
+            return i;
+    }
+
+    return -1;
+}
+
+// Extract the command portion from an incoming framed message. The
+// protocol format is: <CMD>#<ARGS>#<CHECK>@ — this returns <CMD>.
+String SerialConnector::getCommandFromIncomming(String incomming)
+{
+    int cmdEnd = getCharIndex('#', incomming);
+    return incomming.substring(0, cmdEnd);
+}
+
+// Extract the arguments portion from an incoming message: returns the
+// text between the first and second '#' characters.
+String SerialConnector::getArgsFromIncomming(String incomming)
+{
+    int cmdEnd = getCharIndex('#', incomming);
+    String cm = incomming.substring(0, cmdEnd);
+
+    String afterCmd = incomming.substring(cmdEnd + 1, incomming.length());
+    int cmdArgsEnd = getCharIndex('#', afterCmd);
+    return afterCmd.substring(0, cmdArgsEnd);
+}
+
+// Extract the check-bit (final field) from an incoming message: the text
+// after the second '#' character (up to the '@' frame terminator).
+String SerialConnector::getCheckBitFromIncomming(String incomming)
+{
+    int cmdEnd = getCharIndex('#', incomming);
+    String cm = incomming.substring(0, cmdEnd);
+
+    String afterCmd = incomming.substring(cmdEnd + 1, incomming.length());
+    int cmdArgsEnd = getCharIndex('#', afterCmd);
+    return afterCmd.substring(cmdArgsEnd + 1, afterCmd.length());
+}
+
+// Verify that `checkBit` equals the computed check for `<cmd>#<args>`.
+// Returns true when they match, false otherwise.
+bool SerialConnector::verifyCheckBit(String cmd, String args, int checkBit)
+{
+    String toCheck = cmd + "#" + args;
+
+    if (stringToCheckNum(toCheck) == checkBit)
+        return true;
+    else
+        return false;
+}
+
+// Send a repeat (RPT) frame asking the remote to resend the last message.
+void SerialConnector::repeat()
+{
+    String cmd = "RPT##410@";
+    Serial.print(cmd);
+}
+
+// Send an acknowledgement (ACKG) frame that includes the original
+// command's check-bit so the sender can confirm delivery.
+void SerialConnector::acknowledge(int checkBit)
+{
+    String cmd = "ACKG";
+    String toSend = cmd + "#" + (String)checkBit;
+    int checkNum = stringToCheckNum(toSend);
+    String final = toSend + "#" + (String)checkNum + "@";
+    Serial.print(final);
+}
+
+// Build and send a framed command with `cmd` and `args`. Appends a computed
+// check-bit and frame terminator, then waits for follow-up (ack/repeat).
+void SerialConnector::sendCommand(String cmd, String args)
+{
+    String toSend = cmd + "#" + args;
+    int checkNum = stringToCheckNum(toSend);
+    String final = toSend + "#" + (String)checkNum + "@";
+    Serial.print(final);
+
+    afterSendCheck(final);
+}
+
+// After sending a command, read the next frame and handle either a
+// repeat (RPT) request or an acknowledgement (ACKG). For RPT, resend the
+// original command. For ACKG, verify the returned check-bit matches.
+void SerialConnector::afterSendCheck(String cmd)
+{
+    String raw = Serial.readStringUntil('@');
+    if (raw == "")
+        afterSendCheck(cmd);
+
+    String comm = getCommandFromIncomming(raw);
+
+    if (comm == "RPT")
+    {
+        sendCommand(getCommandFromIncomming(cmd), getArgsFromIncomming(cmd));
+    }
+    else if (comm == "ACKG")
+    {
+        int check = getArgsFromIncomming(raw).toInt();
+        int cmdCheck = getCheckBitFromIncomming(cmd).toInt();
+
+        if (check != cmdCheck)
+        {
+            // TODO: Implement a command to resend previous command
+        }
+        else
+        {
+        }
+    }
+}
+
+// Register a callback to be invoked when an acknowledgement frame is
+// received. The callback receives the acknowledgement's args string.
+void SerialConnector::onAcknowledge(void (*handler)(String args))
+{
+    acknowledgeHandler = handler;
+}
+
+// Register a callback to be invoked when a repeat (RPT) frame is
+// received. The handler receives the repeat frame's args.
+void SerialConnector::onRepeat(void (*handler)(String args))
+{
+    repeatHandler = handler;
+}
+
+// Register a callback for the 'CAL-BGN' command. The handler receives the
+// calibration arguments string when calibration begins.
+void SerialConnector::onCalibrationBegin(void (*handler)(String args))
+{
+    calibrationBeginHandler = handler;
+}
+
+// Register a callback for the 'CAL-INT' command. The handler receives the
+// calibration interrupt arguments string when an interrupt occurs.
+void SerialConnector::onCalibrationInterupt(void (*handler)(String args))
+{
+    calibrationInteruptHandler = handler;
+}

test/README

@@ -0,0 +1,11 @@
+
+This directory is intended for PlatformIO Test Runner and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PlatformIO Unit Testing:
+- https://docs.platformio.org/en/latest/advanced/unit-testing/index.html