A Classic Blog

  PP_BATT_VCC : This is the main battery voltage rail that originates directly from the battery connector. It carries the raw battery voltage (typically 3.8V–4.2V, depending on charge level) into the mainboard. It’s the starting point of power distribution and feeds into various subsystems, including the charging and power management circuits. PP_VCC_MAIN : After PP_BATT_VCC, the voltage often passes through protective components (like fuses or MOSFETs) and becomes PP_VCC_MAIN. This rail powers the primary circuits on the board, including the Power Management IC (PMIC) and, indirectly, the charging IC. On the iPhone 12 Pro, this rail is a key intermediary between the battery and downstream power regulation. PP_BUS (or similar intermediate rail)**: Some iPhone designs use an intermediate bus voltage rail (sometimes labeled PP_BUS or a variant) that connects PP_BATT_VCC to the charging IC and other components. This rail might be filtered or regulated slightly before reach...

  🔋 1. Battery (VBAT) Supplies Standby Power The VBAT (Main Battery Line) is always connected to the logic board, even when the iPhone is off. VBAT voltage: ~3.7V-4.2V , depending on battery charge. ⚠️ If VBAT is missing or disconnected, the iPhone will not turn on, even when plugged into a charger. ⚡ 2. Power Management IC (PMIC) is Always Active PMIC (Power Management Integrated Circuit) remains partially active to manage charging, power button detection, and wake-up events. PMIC generates low-power standby voltages to supply essential circuits. These voltages keep the iPhone "ready to turn on" when needed. ⚠️ If PMIC fails, the iPhone will be completely dead (no charging, no response). 📶 3. Always-On Power Rails (Even When Off) Some power rails remain active even when the phone is off, including: Power Rail Voltage Purpose PP_VDD_MAIN 3.7V-4.2V Main power for essential circuits PP3V0_TRTC 3.0V Real-Time Clock (RTC) for system time PP1V8_ALWAYS 1.8V Always-on low-powe...

  🔋 1. Power Source & Initial Activation This stage involves powering the device and initializing voltage regulators . Step 1: Battery or Charger Supplies Power The iPhone receives power from either: The battery (connected via VBAT) The Lightning port (if charging or connected to a computer) VBAT Line (Main Battery Line) VBAT is the main power rail connected directly to the battery. It supplies raw battery voltage (3.7V - 4.35V) to the Power Management IC (PMIC) . If VBAT is missing or disrupted, the phone will not power on . ⚡ 2. Power Management & Voltage Regulation Step 2: Power Management IC (PMIC) Activation The PMIC (Power Management Integrated Circuit) is responsible for regulating voltage and distributing power to various components. The PMIC is controlled by the AP_TO_PM_ENABLE signal , which is triggered when the power button is pressed. Step 3: PMIC Generates Power Rails The PMIC takes the raw VBAT voltage and converts it into different power rails: Power...

  🔹 Stage 1: Power-On & Hardware Initialization This stage handles the basic power flow and hardware activation. 1️⃣ Power Button Pressed Pressing the power button signals the PMU (Power Management Unit) to begin powering up the device. PMU activates components like: CPU (Processor) RAM (Random Access Memory) NAND Storage (Flash Memory) Baseband Processor (For Cellular Communication) Battery Management System 🔹 Stage 2: BootROM Execution (First Bootloader - Immutable Code) Now that the device has power, the processor executes BootROM , the first-stage bootloader stored in read-only memory (ROM) inside the CPU. 2️⃣ BootROM Execution BootROM is the first line of defense in iOS security and cannot be modified. It performs an Initial Integrity Check to verify if the firmware is valid. It loads the Apple Secure Boot Chain , a multi-step process ensuring only Apple-approved software is used. 🔹 Stage 3: Secure Boot Chain & Low-Level Bootloading BootROM now begins executin...

  What are the legal minimum ceiling heights in Queensland? A room that is lower than 2400mm cannot technically be used for habitable living purposes. This includes bedrooms, living rooms, loungerooms, music rooms, dining rooms, playrooms, home theatres and rumpus rooms etc.    Rooms not less than 2100mm can be a kitchen, pantry, laundry, hallway, corridor, storeroom, garage or carparking area. Anything less than 2100mm is classed as a utility room.    What is the minimum ground level? If your property elevation is 6.7 mAHD ( mAHD stands for meters above Australian Height Datum .)  and the Defined Flood Level (DFL) is 9 mAHD, you’ll need to account for the minimum habitable floor level requirements when building a granny flat. Minimum Floor Height Calculation: Defined Flood Level (DFL): 9 mAHD Freeboard Requirement: +0.3 m (300 mm) above the DFL...

 Floodmap Maryborough https://fcrc.spatial.t1cloud.com/spatial/IntraMaps/ApplicationEngine/frontend/mapbuilder/default.htm?configId=e003842b-3af0-44a7-8bd8-45f9880f2c30&liteConfigId=a39f479d-665c-416f-981d-e474fdc44d72&title=Rmxvb2QgTGV2ZWwgUHJlZGljdGlvbnMgTWFyeWJvcm91Z2g=

  Local business owners know digital marketing is critical. Unfortunately, many don’t sustain growth because they cannot maintain consistency or because they run out of ideas. The good news is, effective digital marketing is a beautiful mix of search engine optimization, pay-per-click marketing, content marketing, social media advertising, and more—and with ever-changing trends, there are always ways to come up with new ideas. Yet as a business owner, it can be hard to come up with those new ideas. That’s why we’ve created this guide, which will cover local marketing suggestions and tips in four overarching categories: Local Facebook and Google advertising Local listings and review sites Local SEO Social media marketing Email marketing Community-based marketing Some of these strategies are tried and true, while others may be new to you (rhyme not intentional, but we’ll go with it). The point is, there is something in here for everyone, whether you’re a rookie local marketer or...