Central Update

CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(central)
+
+target_sources(app PRIVATE
+  src/main.c
+)
+
+zephyr_library_include_directories(${ZEPHYR_BASE}/samples/bluetooth)

README.md

@@ -1,27 +1,54 @@
-# Stel Interview Question
-
-## Instruction for Setup
-
-For detailed instructions on setting up the environment, please refer to the [Nordic Semiconductor documentation](https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/installation/install_ncs.html).
-
-## Project Sample
-
-> **Note:** If you want to compile the project, feel free to use any nRF52 boards. You don't need to load the firmware to the device.
-
-You can find the project sample at the following path: `zephyr/samples/bluetooth/central`.
-
-## Questions
-
-### Q1: Filter Device by Name in `device_found` Function
-
-In the `device_found` function, filter the connecting device based on its name. Example: Device with name `DXC`. Please update the `device_found` function using the `bt_data_parse` API to filter by `type: BT_DATA_NAME_COMPLETE`.
-
-### Q2: Support for Multiple Device Connections
-
-The current application only supports a single device connection. Please propose an idea for adding support for multiple device connections and add changes to the current central app.
-
-> **Note:** This is only an interview project. You don't really need to make it work properly. We are able to understand your ideas :)
-
-## Submission
-
-Please create a branch based on your name and submit the central app you changed.
+bt_data_parse accepts three parameters: a buffer of the ad data, a callback function, and a pointer where the parsed data of interest can be stored.
+
+Line 52 and 53 of main.c define the character array that will be used to store the parsed data. The variable decays to a pointer to the first element of the array when passed to bt_data_parse.
+
+bt_data_parse calls find_device_name repeated until false is returns. False indicates the device name has been found and parsing can stop.
+
+Device name is printed using printk.
+
+## Q2 - Implementation Summary
+
+Support for multiple devices is effectively managed by utilizing 3 global variables.
+```c
+static struct bt_conn *conn_connecting = NULL;
+static uint8_t volatile conn_count;
+static bool volatile is_connecting = false;
+```
+bt_conn is the major data structure used in Zephyr's Bluetooth stack that keeps track of a connected device's important information. It is passed to bt_conn_le_create, which creates the connection and adds it to a list of connected devices. 
+```c
+bt_conn_le_create(addr, BT_CONN_LE_CREATE_CONN,
+				BT_LE_CONN_PARAM_DEFAULT, &conn_connecting);
+```
+In the connected function, is_connecting is set back to false, conn_connecting is set back to NULL and conn_count is incremented. Similar logic is used in disconnected callback function.
+```c
+is_connecting = false;
+conn_connecting = NULL;
+conn_count++;
+```
+Main enters an infinite while loop after initiating the first scan. The while loop will check to see if a new scan should be initiated and intermittently yield CPU.
+```c
+k_sleep(K_MSEC(100));
+
+if (conn_count < CONFIG_BT_MAX_CONN && !is_connecting) {
+    start_scan();
+}
+```
+## Other Functionality Implemented
+- The settings subsystem was configured to store device pairing information.
+- SMP was configured for additional security.
+- Privacy was configured for added anonymity.
+## prj.conf
+- System is configured to support up to 5 simultaneous connections and remember up to 10 devices.
+```
+CONFIG_BT=y 
+CONFIG_BT_CENTRAL=y
+CONFIG_BT_MAX_CONN=5
+CONFIG_BT_MAX_PAIRED=10 
+CONFIG_BT_SMP=y 
+CONFIG_BT_PRIVACY=y
+CONFIG_BT_SETTINGS=y
+CONFIG_SETTINGS=y
+CONFIG_BT_HCI=y
+```
+### Files Changed
+main.c and prj.conf

README.rst

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+.. _bluetooth_central:
+
+Bluetooth: Central
+##################
+
+Overview
+********
+
+Application demonstrating very basic BLE Central role functionality by scanning
+for other BLE devices and establishing a connection to the first one with a
+strong enough signal.
+
+
+
+Requirements
+************
+
+* BlueZ running on the host, or
+* A board with BLE support
+
+Building and Running
+********************
+This sample can be found under :zephyr_file:`samples/bluetooth/central` in the
+Zephyr tree.
+
+See :ref:`bluetooth samples section <bluetooth-samples>` for details.

boards/rv32m1_vega_openisa_rv32m1_ri5cy.overlay

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+/*
+ * Copyright 2019 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&lptmr1 {
+	interrupt-parent = <&intmux0_ch2>;
+};
+
+&intmux0_ch2 {
+	status = "okay";
+};
+
+&intmux0_ch3 {
+	status = "okay";
+};
+
+&generic_fsk {
+	interrupt-parent = <&intmux0_ch3>;
+	status = "okay";
+};

build/CMakeCache.txt

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+# This is the CMakeCache file.
+# For build in directory: /Users/jacobjunk/dev/zephyr/bt_central/build
+# It was generated by CMake: /opt/nordic/ncs/toolchains/f8037e9b83/Cellar/cmake/3.21.0/bin/cmake
+# You can edit this file to change values found and used by cmake.
+# If you do not want to change any of the values, simply exit the editor.
+# If you do want to change a value, simply edit, save, and exit the editor.
+# The syntax for the file is as follows:
+# KEY:TYPE=VALUE
+# KEY is the name of a variable in the cache.
+# TYPE is a hint to GUIs for the type of VALUE, DO NOT EDIT TYPE!.
+# VALUE is the current value for the KEY.
+
+########################
+# EXTERNAL cache entries
+########################
+
+//Application Binary Directory
+APPLICATION_BINARY_DIR:PATH=/Users/jacobjunk/dev/zephyr/bt_central/build
+
+//Application Source Directory
+APPLICATION_SOURCE_DIR:PATH=/Users/jacobjunk/dev/zephyr/bt_central
+
+//Selected board
+BOARD:STRING=rv32m1_vega_openisa_rv32m1_ri5cy
+
+//No help, variable specified on the command line.
+BOARD_ROOT:UNINITIALIZED=/opt/nordic/ncs/v2.7.0/zephyr/samples/bluetooth/central;/Users/jacobjunk/dev/zephyr/bt_central;/opt/nordic/ncs/v2.7.0/zephyr/samples/bluetooth/central_hr
+
+//Path to a program.
+CCACHE_FOUND:FILEPATH=/opt/nordic/ncs/toolchains/f8037e9b83/bin/ccache
+
+//No help, variable specified on the command line.
+NCS_TOOLCHAIN_VERSION:UNINITIALIZED=NONE
+
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+WEST_PYTHON:UNINITIALIZED=/opt/nordic/ncs/toolchains/f8037e9b83/opt/[email protected]/bin/python3.9
+
+//Zephyr base
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+
+//The directory containing a CMake configuration file for ZephyrAppConfiguration.
+ZephyrAppConfiguration_DIR:PATH=ZephyrAppConfiguration_DIR-NOTFOUND
+
+//The directory containing a CMake configuration file for ZephyrBuildConfiguration.
+ZephyrBuildConfiguration_DIR:PATH=/opt/nordic/ncs/v2.7.0/nrf/share/zephyrbuild-package/cmake
+
+//The directory containing a CMake configuration file for Zephyr.
+Zephyr_DIR:PATH=/opt/nordic/ncs/v2.7.0/zephyr/share/zephyr-package/cmake
+
+
+########################
+# INTERNAL cache entries
+########################
+
+//This is the directory where this CMakeCache.txt was created
+CMAKE_CACHEFILE_DIR:INTERNAL=/Users/jacobjunk/dev/zephyr/bt_central/build
+//Major version of cmake used to create the current loaded cache
+CMAKE_CACHE_MAJOR_VERSION:INTERNAL=3
+//Minor version of cmake used to create the current loaded cache
+CMAKE_CACHE_MINOR_VERSION:INTERNAL=21
+//Patch version of cmake used to create the current loaded cache
+CMAKE_CACHE_PATCH_VERSION:INTERNAL=0
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+//Path to cpack program executable.
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+//Path to ctest program executable.
+CMAKE_CTEST_COMMAND:INTERNAL=/opt/nordic/ncs/toolchains/f8037e9b83/Cellar/cmake/3.21.0/bin/ctest
+//Name of external makefile project generator.
+CMAKE_EXTRA_GENERATOR:INTERNAL=
+//Name of generator.
+CMAKE_GENERATOR:INTERNAL=Ninja
+//Generator instance identifier.
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+//Name of generator platform.
+CMAKE_GENERATOR_PLATFORM:INTERNAL=
+//Name of generator toolset.
+CMAKE_GENERATOR_TOOLSET:INTERNAL=
+//Source directory with the top level CMakeLists.txt file for this
+// project
+CMAKE_HOME_DIRECTORY:INTERNAL=/Users/jacobjunk/dev/zephyr/bt_central
+//number of local generators
+CMAKE_NUMBER_OF_MAKEFILES:INTERNAL=1
+//Path to CMake installation.
+CMAKE_ROOT:INTERNAL=/opt/nordic/ncs/toolchains/f8037e9b83/Cellar/cmake/3.21.0/share/cmake
+//Details about finding Python3
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+//West
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+_Python3_EXECUTABLE:INTERNAL=/opt/nordic/ncs/toolchains/f8037e9b83/opt/[email protected]/bin/python3.9
+//Python3 Properties
+_Python3_INTERPRETER_PROPERTIES:INTERNAL=Python;3;9;6;64;;cpython-39-darwin;/opt/nordic/ncs/toolchains/f8037e9b83/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib/python3.9;/opt/nordic/ncs/toolchains/f8037e9b83/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib/python3.9;/opt/nordic/ncs/toolchains/f8037e9b83/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages;/opt/nordic/ncs/toolchains/f8037e9b83/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages
+_Python3_INTERPRETER_SIGNATURE:INTERNAL=396ffb7fd36708041338b90b48c8cc7b
+

build/CMakeFiles/cmake.check_cache

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+# This file is generated by cmake for dependency checking of the CMakeCache.txt file