From 163a91ea481e20f6ac5ccef86463455e9644849b Mon Sep 17 00:00:00 2001
From: liamcottle <liam@liamcottle.com>
Date: Sun, 14 Jul 2024 19:10:40 +1200
Subject: [PATCH] refactor code

---
 index.html           | 176 ++++++++---------------
 nrf52_dfu_flasher.js | 327 ++++++++++++++++++++++++-------------------
 rnode.js             |  27 ++--
 todo.txt             |  61 ++++++++
 4 files changed, 322 insertions(+), 269 deletions(-)
 create mode 100644 todo.txt

diff --git a/index.html b/index.html
index 73a2647..7ee5494 100644
--- a/index.html
+++ b/index.html
@@ -33,6 +33,12 @@
         </button>
     </div>
 
+    <div>
+        <button @click="detect" class="border px-2 bg-gray-100 hover:bg-gray-200 rounded">
+            Detect
+        </button>
+    </div>
+
 </div>
 
 <script>
@@ -46,36 +52,71 @@
 
         },
         methods: {
-            async connect() {
+            async askForSerialPort() {
 
                 if(!navigator.serial){
-                    alert("Serial is not supported in this browser");
-                    return;
+                    alert("Web Serial is not supported in this browser");
+                    return null;
                 }
 
                 // ask user to select device
-                const serialPort = await navigator.serial.requestPort({
+                return await navigator.serial.requestPort({
                     filters: [],
                 });
 
-                this.flasher = new Nrf52DfuFlasher(serialPort);
+            },
+            async enterDfuMode() {
 
-                // await this.flasher.enterDfuMode();
-
-                return;
-
-                await serialPort.open({
-                    baudRate: RNode.BAUD_RATE,
-                });
-
-                const rnode = RNode.fromSerialPort(serialPort);
-
-                if(!await rnode.detect()){
-                    console.log("device is not an rnode");
+                // ask for serial port
+                const serialPort = await this.askForSerialPort();
+                if(!serialPort){
                     return;
                 }
 
-                // dump node info
+                // enter dfu mode
+                const flasher = new Nrf52DfuFlasher(serialPort);
+                await flasher.enterDfuMode();
+
+            },
+            async flash() {
+
+                // ensure firmware file selected
+                const file = this.$refs["file"].files[0];
+                if(!file){
+                    alert("Select a firmware file first");
+                    return;
+                }
+
+                // ask for serial port
+                const serialPort = await this.askForSerialPort();
+                if(!serialPort){
+                    return;
+                }
+
+                // flash file
+                const flasher = new Nrf52DfuFlasher(serialPort);
+                await flasher.flash(file);
+
+            },
+            async detect() {
+
+                // ask for serial port
+                const serialPort = await this.askForSerialPort();
+                if(!serialPort){
+                    return;
+                }
+
+                // check if device is an rnode
+                const rnode = await RNode.fromSerialPort(serialPort);
+                const isRNode = await rnode.detect();
+                if(!isRNode){
+                    alert("Selected device is not an RNode!");
+                    return;
+                }
+
+                const firmwareVersion = await rnode.getFirmwareVersion();
+                alert("RNode has firmware v" + firmwareVersion);
+
                 console.log({
                     firmware_version: await rnode.getFirmwareVersion(),
                     platform: await rnode.getPlatform(),
@@ -96,104 +137,7 @@
                     rssi_stat: await rnode.getRssiStat(),
                 });
 
-                // console.log(response.map(x => x.toString(16).padStart(2, '0')).join(''));
-
-
-                // rnode.device_probe()
-                // rnode.download_eeprom()
-
-                // if rnode.provisioned and rnode.signature_valid:
-                // This device is already installed and provisioned. No further action will
-
-                // if rnode.detected:
-                // The device seems to have an RNode firmware installed, but it was not provisioned correctly, or it is corrupt
-                // We are going to reinstall the correct firmware and provision it.
-                // else
-                // It looks like this is a fresh device with no RNode firmware.
-
-                // selected_product = ROM.PRODUCT_RAK4631
-                // selected_platform = None
-                // selected_model = None
-                // selected_mcu = ROM.MCU_NRF52
-
-                // print("\nWhat band is this RAK4631 for?\n")
-
-                // print("[1] 433 MHz")
-                // selected_model = ROM.MODEL_11
-                // selected_platform = ROM.PLATFORM_NRF52
-
-                // print("[2] 868 MHz")
-                // print("[3] 915 MHz")
-                // print("[4] 923 MHz")
-                // selected_model = ROM.MODEL_12
-                // selected_platform = ROM.PLATFORM_NRF52
-
-                // fw_filename = models[selected_model][4]
-                // if fw_filename == None:
-                // Sorry, no firmware for your board currently exists.
-
-                // args.key = True
-                // args.port = selected_port.device
-                // args.platform = selected_platform
-                // args.hwrev = 1
-                // mapped_model = selected_model
-                // mapped_product = selected_product
-                // args.update = False
-                // args.flash = True
-
-                // ensure_firmware_file(fw_filename)
-
-                // get or generate device signing key (rns identity is used)
-                // get or generate eeprom signing key (rsa private key is generated)
-                // get partition hash (sha256 of firmware file for rak)
-
-                // extract firmware zip folder
-
-                // get flasher call
-                // adafruit-nrfutil dfu serial --package fw_filename -p args.port -b 115200 -t 1200
-                // adafruit-nrfutil dfu serial --package ~/Downloads/rnode_firmware_rak4631.zip -p /dev/cu.usbmodem14401 -b 115200 -t 1200
-                // --package dfu filename
-                // -p comport
-                // -b baud rate
-                // -t Open port with specified baud then close it, before uploading
-
-                // https://github.com/adafruit/Adafruit_nRF52_nrfutil/blob/master/nordicsemi/__main__.py
-                // https://github.com/adafruit/Adafruit_nRF52_nrfutil/blob/master/nordicsemi/dfu/dfu_transport_serial.py#L49
-                // https://github.com/markqvist/Reticulum/discussions/471
-
-
-            },
-            async initFlasher() {
-
-                if(!navigator.serial){
-                    alert("Web Serial is not supported in this browser");
-                    return;
-                }
-
-                // ask user to select device
-                const serialPort = await navigator.serial.requestPort({
-                    filters: [],
-                });
-
-                return new Nrf52DfuFlasher(serialPort);
-
-            },
-            async enterDfuMode() {
-                const flasher = await this.initFlasher();
-                await flasher.enterDfuMode();
-            },
-            async flash() {
-
-                // ensure firmware file selected
-                const file = this.$refs["file"].files[0];
-                if(!file){
-                    alert("Select a firmware file first");
-                    return;
-                }
-
-                // flash file
-                const flasher = await this.initFlasher();
-                await flasher.flash(file);
+                await rnode.close();
 
             },
         },
diff --git a/nrf52_dfu_flasher.js b/nrf52_dfu_flasher.js
index 8a0bd36..dbae1f1 100644
--- a/nrf52_dfu_flasher.js
+++ b/nrf52_dfu_flasher.js
@@ -1,5 +1,5 @@
 /**
- * A web based nRF52 flasher based on:
+ * A Web Serial based nRF52 flasher written by liam@liamcottle.com based on dfu_transport.serial.py
  * https://github.com/adafruit/Adafruit_nRF52_nrfutil/blob/master/nordicsemi/dfu/dfu_transport_serial.py
  */
 class Nrf52DfuFlasher {
@@ -10,7 +10,7 @@ class Nrf52DfuFlasher {
 
     FLASH_BAUD = 115200;
 
-    HexType_APPLICATION = 4;
+    HEX_TYPE_APPLICATION = 4;
 
     DFU_INIT_PACKET = 1;
     DFU_START_PACKET = 3;
@@ -31,15 +31,30 @@ class Nrf52DfuFlasher {
 
     constructor(serialPort) {
         this.serialPort = serialPort;
-        this.sequence_number = 0;
+        this.sequenceNumber = 0;
         this.sd_size = 0;
         this.total_size = 0;
     }
 
-    async send_packet(data) {
+    /**
+     * Waits for the provided milliseconds, and then resolves.
+     * @param millis
+     * @returns {Promise<void>}
+     */
+    async sleepMillis(millis) {
+        await new Promise((resolve) => {
+            setTimeout(resolve, millis);
+        });
+    }
+
+    /**
+     * Writes the provided data to the Serial Port.
+     * @param data
+     * @returns {Promise<void>}
+     */
+    async sendPacket(data) {
         const writer = this.serialPort.writable.getWriter();
         try {
-            console.log("writing", data);
             await writer.write(new Uint8Array(data));
         } finally {
             writer.releaseLock();
@@ -47,7 +62,7 @@ class Nrf52DfuFlasher {
     }
 
     /**
-     * Puts an nRF52 board into DFU mode by quickly opening and closing a serial port
+     * Puts an nRF52 board into DFU mode by quickly opening and closing a serial port.
      * @returns {Promise<void>}
      */
     async enterDfuMode() {
@@ -58,20 +73,21 @@ class Nrf52DfuFlasher {
         });
 
         // wait SERIAL_PORT_OPEN_WAIT_TIME before closing port
-        await new Promise((resolve, reject) => {
-            setTimeout(resolve, this.SERIAL_PORT_OPEN_WAIT_TIME * 1000);
-        });
+        await this.sleepMillis(this.SERIAL_PORT_OPEN_WAIT_TIME * 1000);
 
         // close port
         await this.serialPort.close();
 
         // wait TOUCH_RESET_WAIT_TIME for device to enter into DFU mode
-        await new Promise((resolve, reject) => {
-            setTimeout(resolve, this.TOUCH_RESET_WAIT_TIME * 1000);
-        });
+        await this.sleepMillis(this.TOUCH_RESET_WAIT_TIME * 1000);
 
     }
 
+    /**
+     * Flashes the provided firmware zip.
+     * @param firmwareZipBlob
+     * @returns {Promise<void>}
+     */
     async flash(firmwareZipBlob) {
 
         // read zip file
@@ -81,6 +97,9 @@ class Nrf52DfuFlasher {
 
         // find manifest file
         const manifestFile = zipEntries.find((zipEntry) => zipEntry.filename === "manifest.json");
+        if(!manifestFile){
+            throw "manifest.json not found in firmware file!";
+        }
 
         // read manifest file as text
         const text = await manifestFile.getData(new window.zip.TextWriter());
@@ -89,29 +108,33 @@ class Nrf52DfuFlasher {
         const json = JSON.parse(text);
         const manifest = json.manifest;
 
-        console.log(manifest);
-
+        // todo softdevice_bootloader
         // if self.manifest.softdevice_bootloader:
         // self._dfu_send_image(HexType.SD_BL, self.manifest.softdevice_bootloader)
-        //
+
+        // todo softdevice
         // if self.manifest.softdevice:
         // self._dfu_send_image(HexType.SOFTDEVICE, self.manifest.softdevice)
-        //
+
+        // todo bootloader
         // if self.manifest.bootloader:
         // self._dfu_send_image(HexType.BOOTLOADER, self.manifest.bootloader)
 
         // flash application image
         if(manifest.application){
-            await this.dfuSendImage(this.HexType_APPLICATION, zipEntries, manifest.application);
+            await this.dfuSendImage(this.HEX_TYPE_APPLICATION, zipEntries, manifest.application);
         }
 
     }
 
-    async dfuSendImage(program_mode, zipEntries, firmware_manifest) {
-
-        if(!firmware_manifest){
-            throw "firmware_manifest must be provided.";
-        }
+    /**
+     * Sends the firmware image to the device in DFU mode.
+     * @param programMode
+     * @param zipEntries
+     * @param firmwareManifest
+     * @returns {Promise<void>}
+     */
+    async dfuSendImage(programMode, zipEntries, firmwareManifest) {
 
         // open port
         await this.serialPort.open({
@@ -119,49 +142,39 @@ class Nrf52DfuFlasher {
         });
 
         // wait SERIAL_PORT_OPEN_WAIT_TIME
-        await new Promise((resolve, reject) => {
-            setTimeout(resolve, this.SERIAL_PORT_OPEN_WAIT_TIME * 1000);
-        });
+        await this.sleepMillis(this.SERIAL_PORT_OPEN_WAIT_TIME * 1000);
 
-        var softdevice_size = 0
-        var bootloader_size = 0
-        var application_size = 0
+        // file sizes
+        var softdeviceSize = 0
+        var bootloaderSize = 0
+        var applicationSize = 0
 
         // read bin file (firmware)
-        const binFile = zipEntries.find((zipEntry) => zipEntry.filename === firmware_manifest.bin_file);
+        const binFile = zipEntries.find((zipEntry) => zipEntry.filename === firmwareManifest.bin_file);
         const firmware = await binFile.getData(new window.zip.Uint8ArrayWriter());
-        console.log(firmware);
 
         // read dat file (init packet)
-        const datFile = zipEntries.find((zipEntry) => zipEntry.filename === firmware_manifest.dat_file);
+        const datFile = zipEntries.find((zipEntry) => zipEntry.filename === firmwareManifest.dat_file);
         const init_packet = await datFile.getData(new window.zip.Uint8ArrayWriter());
-        console.log(init_packet);
 
         // only support flashing application for now
-        if(program_mode !== this.HexType_APPLICATION){
+        if(programMode !== this.HEX_TYPE_APPLICATION){
             throw "not implemented";
         }
 
-        if(program_mode === this.HexType_APPLICATION){
-            application_size = firmware.length;
-            console.log("app size", application_size);
+        // determine application size
+        if(programMode === this.HEX_TYPE_APPLICATION){
+            applicationSize = firmware.length;
         }
 
-        // todo test this works...
         console.log("Sending DFU start packet");
-        await this.send_start_dfu(program_mode, softdevice_size, bootloader_size, application_size);
+        await this.sendStartDfu(programMode, softdeviceSize, bootloaderSize, applicationSize);
 
         console.log("Sending DFU init packet");
-        await this.send_init_packet(init_packet);
+        await this.sendInitPacket(init_packet);
 
         console.log("Sending firmware file")
-        await this.send_firmware(firmware);
-
-        // console.log("Sending validate firmware")
-        // await this.send_validate_firmware();
-        //
-        // console.log("Sending activate firmware")
-        // await this.send_activate_firmware();
+        await this.sendFirmware(firmware);
 
         // close port
         console.log("Closing Port");
@@ -174,20 +187,19 @@ class Nrf52DfuFlasher {
 
     }
 
-    // confirmed working
+    /**
+     * Calculates CRC16 on the provided binaryData
+     * @param {Uint8Array} binaryData - Array with data to run CRC16 calculation on
+     * @param {number} crc - CRC value to start calculation with
+     * @return {number} - Calculated CRC value of binaryData
+     */
     calcCrc16(binaryData, crc = 0xffff) {
-        /**
-         * Calculates CRC16 on binaryData
-         *
-         * @param {Uint8Array} binaryData - Array with data to run CRC16 calculation on
-         * @param {number} crc - CRC value to start calculation with
-         * @return {number} - Calculated CRC value of binaryData
-         */
-        if (!(binaryData instanceof Uint8Array)) {
+
+        if(!(binaryData instanceof Uint8Array)){
             throw new Error("calcCrc16 requires Uint8Array input");
         }
 
-        for (let b of binaryData) {
+        for(let b of binaryData){
             crc = (crc >> 8 & 0x00FF) | (crc << 8 & 0xFF00);
             crc ^= b;
             crc ^= (crc & 0x00FF) >> 4;
@@ -196,26 +208,25 @@ class Nrf52DfuFlasher {
         }
 
         return crc & 0xFFFF;
+
     }
 
-    // confirmed working
+    /**
+     * Encode esc characters in a SLIP package.
+     * Replace 0xC0 with 0xDBDC and 0xDB with 0xDBDD.
+     * @param dataIn
+     * @returns {*[]}
+     */
     slipEncodeEscChars(dataIn) {
-        /**
-         * Encode esc characters in a SLIP package.
-         *
-         * Replace 0xC0 with 0xDBDC and 0xDB with 0xDBDD.
-         *
-         * @param {string} dataIn - String to encode
-         * @return {string} - String with encoded packet
-         */
+
         let result = [];
 
-        for (let i = 0; i < dataIn.length; i++) {
+        for(let i = 0; i < dataIn.length; i++){
             let char = dataIn[i];
-            if (char === 0xC0) {
+            if(char === 0xC0){
                 result.push(0xDB);
                 result.push(0xDC);
-            } else if (char === 0xDB) {
+            } else if(char === 0xDB) {
                 result.push(0xDB);
                 result.push(0xDD);
             } else {
@@ -223,125 +234,157 @@ class Nrf52DfuFlasher {
             }
         }
 
-        // return String.fromCharCode(...result);
         return result;
 
     }
 
-    // seems to be working as expected, was hard to test
-    frameToHciPacket(frame) {
+    /**
+     * Creates an HCI packet from the provided frame data.
+     * https://github.com/adafruit/Adafruit_nRF52_nrfutil/blob/master/nordicsemi/dfu/dfu_transport_serial.py#L332
+     * @param frame
+     * @returns {*[]}
+     */
+    createHciPacketFromFrame(frame) {
 
-        this.sequence_number = (this.sequence_number + 1) % 8;
+        // increase sequence number, but roll over at 8
+        this.sequenceNumber = (this.sequenceNumber + 1) % 8;
 
-        const slip_bytes = this.slipPartsToFourBytes(
-            this.sequence_number,
+        // create slip header
+        const slipHeaderBytes = this.createSlipHeader(
+            this.sequenceNumber,
             this.DATA_INTEGRITY_CHECK_PRESENT,
             this.RELIABLE_PACKET,
             this.HCI_PACKET_TYPE,
             frame.length,
         );
 
-        let tempData = [
-            ...slip_bytes,
+        // create packet data
+        let data = [
+            ...slipHeaderBytes,
             ...frame,
         ];
 
-        // Add escape characters
-        const crc = this.calcCrc16(new Uint8Array(tempData), 0xffff);
-        tempData.push(crc & 0xFF)
-        tempData.push((crc & 0xFF00) >> 8)
+        // add crc of data
+        const crc = this.calcCrc16(new Uint8Array(data), 0xffff);
+        data.push(crc & 0xFF);
+        data.push((crc & 0xFF00) >> 8);
 
+        // add escape characters
         return [
             0xc0,
-            ...this.slipEncodeEscChars(tempData),
+            ...this.slipEncodeEscChars(data),
             0xc0,
         ];
 
     }
 
-    get_erase_wait_time() {
-        // timeout is not least than 0.5 seconds
+    /**
+     * Calculate how long we should wait for erasing data.
+     * @returns {number}
+     */
+    getEraseWaitTime() {
+        // always wait at least 0.5 seconds
         return Math.max(0.5, ((this.total_size / this.FLASH_PAGE_SIZE) + 1) * this.FLASH_PAGE_ERASE_TIME);
     }
 
-    // frame seems to be fine
-    async send_start_dfu(mode, softdevice_size = 0, bootloader_size = 0, app_size = 0){
+    /**
+     * Constructs the image size packet sent in the DFU Start packet.
+     * @param softdeviceSize
+     * @param bootloaderSize
+     * @param appSize
+     * @returns {number[]}
+     */
+    createImageSizePacket(softdeviceSize = 0, bootloaderSize = 0, appSize = 0) {
+        return [
+            ...this.int32ToBytes(softdeviceSize),
+            ...this.int32ToBytes(bootloaderSize),
+            ...this.int32ToBytes(appSize),
+        ];
+    }
 
+    /**
+     * Sends the DFU Start packet to the device.
+     * @param mode
+     * @param softdevice_size
+     * @param bootloader_size
+     * @param app_size
+     * @returns {Promise<void>}
+     */
+    async sendStartDfu(mode, softdevice_size = 0, bootloader_size = 0, app_size = 0){
+
+        // create frame
         const frame = [
-            ...this.toBytesInt32(this.DFU_START_PACKET),
-            ...this.toBytesInt32(mode),
-            ...this.create_image_size_packet(softdevice_size, bootloader_size, app_size),
+            ...this.int32ToBytes(this.DFU_START_PACKET),
+            ...this.int32ToBytes(mode),
+            ...this.createImageSizePacket(softdevice_size, bootloader_size, app_size),
         ];
 
-        await this.send_packet(this.frameToHciPacket(frame));
+        // send hci packet
+        await this.sendPacket(this.createHciPacketFromFrame(frame));
 
+        // remember file sizes for calculating erase wait time
         this.sd_size = softdevice_size;
         this.total_size = softdevice_size + bootloader_size + app_size;
 
-        await new Promise((resolve, reject) => {
-            setTimeout(resolve, this.get_erase_wait_time() * 1000);
-        });
+        // wait for initial erase
+        await this.sleepMillis(this.getEraseWaitTime() * 1000);
 
     }
 
-    async send_init_packet(init_packet){
+    /**
+     * Sends the DFU Init packet to the device.
+     * @param initPacket
+     * @returns {Promise<void>}
+     */
+    async sendInitPacket(initPacket){
 
+        // create frame
         const frame = [
-            ...this.toBytesInt32(this.DFU_INIT_PACKET),
-            ...init_packet,
-            ...this.toBytesInt16(0x0000), // Padding required
+            ...this.int32ToBytes(this.DFU_INIT_PACKET),
+            ...initPacket,
+            ...this.int16ToBytes(0x0000), // padding required
         ];
 
-        await this.send_packet(this.frameToHciPacket(frame));
+        // send hci packet
+        await this.sendPacket(this.createHciPacketFromFrame(frame));
 
     }
 
-    async send_firmware(firmware) {
+    /**
+     * Sends the firmware file to the device in multiple chunks.
+     * @param firmware
+     * @returns {Promise<void>}
+     */
+    async sendFirmware(firmware) {
 
-        const frames = [];
+        const packets = [];
 
-        // seems to be chunking properly
+        // chunk firmware into separate packets
         for(let i = 0; i < firmware.length; i += this.DFU_PACKET_MAX_SIZE){
-            frames.push(this.frameToHciPacket([
-                ...this.toBytesInt32(this.DFU_DATA_PACKET),
+            packets.push(this.createHciPacketFromFrame([
+                ...this.int32ToBytes(this.DFU_DATA_PACKET),
                 ...firmware.slice(i, i + this.DFU_PACKET_MAX_SIZE),
             ]));
         }
 
-        // todo rename to packet?
-        for(var i = 0; i < frames.length; i++){
+        // send each packet one after the other
+        for(var i = 0; i < packets.length; i++){
 
-            const frame = frames[i];
+            // send packet
+            await this.sendPacket(packets[i]);
 
-            await this.send_packet(frame);
-
-            // wait a bit to allow device to write before sending next frame
-            await new Promise((resolve, reject) => {
-                setTimeout(resolve, this.FLASH_PAGE_WRITE_TIME * 1000);
-            });
+            // wait a bit to allow device to write before sending next packet
+            await this.sleepMillis(this.FLASH_PAGE_WRITE_TIME * 1000);
 
         }
 
-        // Wait for last page to write
-        await new Promise((resolve, reject) => {
-            setTimeout(resolve, this.FLASH_PAGE_WRITE_TIME * 1000);
-        });
-
-        // Send data stop packet
-        await this.send_packet(this.frameToHciPacket([
-            ...this.toBytesInt32(this.DFU_STOP_DATA_PACKET),
+        // finished sending firmware, send DFU Stop Data packet
+        await this.sendPacket(this.createHciPacketFromFrame([
+            ...this.int32ToBytes(this.DFU_STOP_DATA_PACKET),
         ]));
 
     }
 
-    async send_validate_firmware() {
-        // no op for usb
-    }
-
-    async send_activate_firmware() {
-        // no op for usb
-    }
-
     /**
      * Creates a SLIP header.
      *
@@ -355,8 +398,7 @@ class Nrf52DfuFlasher {
      * @param {number} pktLen - Packet length
      * @return {Uint8Array} - SLIP header
      */
-    // confirmed working
-    slipPartsToFourBytes(seq, dip, rp, pktType, pktLen) {
+    createSlipHeader(seq, dip, rp, pktType, pktLen) {
         let ints = [0, 0, 0, 0];
         ints[0] = seq | (((seq + 1) % 8) << 3) | (dip << 6) | (rp << 7);
         ints[1] = pktType | ((pktLen & 0x000F) << 4);
@@ -365,17 +407,12 @@ class Nrf52DfuFlasher {
         return new Uint8Array(ints);
     }
 
-    // confirmed working
-    create_image_size_packet(softdevice_size = 0, bootloader_size = 0, app_size = 0) {
-        return [
-            ...this.toBytesInt32(softdevice_size),
-            ...this.toBytesInt32(bootloader_size),
-            ...this.toBytesInt32(app_size),
-        ];
-    }
-
-    // confirmed working
-    toBytesInt32(num){
+    /**
+     * Converts the provided int32 to 4 bytes.
+     * @param num
+     * @returns {number[]}
+     */
+    int32ToBytes(num){
         return [
             (num & 0x000000ff),
             (num & 0x0000ff00) >> 8,
@@ -384,10 +421,14 @@ class Nrf52DfuFlasher {
         ];
     }
 
-    // confirmed working
-    toBytesInt16(num){
+    /**
+     * Converts the provided int16 to 2 bytes.
+     * @param num
+     * @returns {number[]}
+     */
+    int16ToBytes(num){
         return [
-            num & 0x00FF,
+            (num & 0x00FF),
             (num & 0xFF00) >> 8,
         ];
     }
diff --git a/rnode.js b/rnode.js
index 593d78f..3d8e09c 100644
--- a/rnode.js
+++ b/rnode.js
@@ -1,7 +1,5 @@
 class RNode {
 
-    static BAUD_RATE = 115200;
-
     KISS_FEND = 0xC0;
     KISS_FESC = 0xDB;
     KISS_TFEND = 0xDC;
@@ -60,16 +58,25 @@ class RNode {
     HASH_TYPE_TARGET_FIRMWARE = 0x01;
     HASH_TYPE_FIRMWARE = 0x02;
 
-    constructor() {
-        this.readable = null;
-        this.writable = null;
+    constructor(serialPort) {
+        this.serialPort = serialPort;
+        this.readable = serialPort.readable;
+        this.writable = serialPort.writable;
     }
 
-    static fromSerialPort(port) {
-        const rnode = new RNode();
-        rnode.readable = port.readable;
-        rnode.writable = port.writable;
-        return rnode;
+    static async fromSerialPort(serialPort) {
+
+        // open port
+        await serialPort.open({
+            baudRate: 115200,
+        });
+
+        return new RNode(serialPort);
+
+    }
+
+    async close() {
+        await this.serialPort.close();
     }
 
     async write(bytes) {
diff --git a/todo.txt b/todo.txt
new file mode 100644
index 0000000..eef642f
--- /dev/null
+++ b/todo.txt
@@ -0,0 +1,61 @@
+rnode.device_probe()
+rnode.download_eeprom()
+
+if rnode.provisioned and rnode.signature_valid:
+This device is already installed and provisioned. No further action will
+
+if rnode.detected:
+The device seems to have an RNode firmware installed, but it was not provisioned correctly, or it is corrupt
+We are going to reinstall the correct firmware and provision it.
+else
+It looks like this is a fresh device with no RNode firmware.
+
+selected_product = ROM.PRODUCT_RAK4631
+selected_platform = None
+selected_model = None
+selected_mcu = ROM.MCU_NRF52
+
+print("\nWhat band is this RAK4631 for?\n")
+
+print("[1] 433 MHz")
+selected_model = ROM.MODEL_11
+selected_platform = ROM.PLATFORM_NRF52
+
+print("[2] 868 MHz")
+print("[3] 915 MHz")
+print("[4] 923 MHz")
+selected_model = ROM.MODEL_12
+selected_platform = ROM.PLATFORM_NRF52
+
+fw_filename = models[selected_model][4]
+if fw_filename == None:
+Sorry, no firmware for your board currently exists.
+
+args.key = True
+args.port = selected_port.device
+args.platform = selected_platform
+args.hwrev = 1
+mapped_model = selected_model
+mapped_product = selected_product
+args.update = False
+args.flash = True
+
+ensure_firmware_file(fw_filename)
+
+get or generate device signing key (rns identity is used)
+get or generate eeprom signing key (rsa private key is generated)
+get partition hash (sha256 of firmware file for rak)
+
+extract firmware zip folder
+
+get flasher call
+adafruit-nrfutil dfu serial --package fw_filename -p args.port -b 115200 -t 1200
+adafruit-nrfutil dfu serial --package ~/Downloads/rnode_firmware_rak4631.zip -p /dev/cu.usbmodem14401 -b 115200 -t 1200
+--package dfu filename
+-p comport
+-b baud rate
+-t Open port with specified baud then close it, before uploading
+
+https://github.com/adafruit/Adafruit_nRF52_nrfutil/blob/master/nordicsemi/__main__.py
+https://github.com/adafruit/Adafruit_nRF52_nrfutil/blob/master/nordicsemi/dfu/dfu_transport_serial.py#L49
+https://github.com/markqvist/Reticulum/discussions/471
\ No newline at end of file