K2 USB-C Meter Download Manuals Firmware PC software(11/25)

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K2 USB-C Voltage and Current Meter User Manua

US  https://www.amazon.com/dp/B0FZWGRLNT
DE  https://www.amazon.de/dp/B0FZWGRLNT
JP   https://www.amazon.co.jp/dp/B0FZWGRLNT

K2 Overview

• RTOS real-time operating system + WIUI human-machine interface
• 32-bit high-speed CPU
• Independent 16-bit high-precision ADC sampling chip
• Standalone electronic storage for data logging, retains data on power-off
• High-speed sampling with fast refresh rate
• 24P pass-through high-current, high-conductivity USB-C terminals
  
  

• Do NOT connect HID power during PD measurement, as K2 requires multiple restarts for accurate detection.
  
  

K2 Features

• PD3.1 support – 28V EPR and AVS protocol triggering
• Supports detection and triggering of multiple fast-charging protocols
• Unified 4D interface – WIOS + WIUI + PC
• 240 MHz ultra-high-speed M4F 32-bit CPU with FPU hardware acceleration
• Independent ADC sampling + on-chip 2 MHz high-speed AD
• Spectrum analysis – simultaneously track charger ripple and frequency characteristics
• Built-in capacity calculation
• Built-in gravity sensor – supports automatic screen rotation
  
  

K2 Specifications

Voltage Measurement:

• DC 3.3–48 V (K2-237)
• DC 3.3–36 V (K2-226)
• Voltage Resolution: 0.0001 V
  
  

Current Measurement:

• Measurement Range: 6 A (10 A short-term peak)
• Current Resolution: 0.0001 A (bidirectional)
• 6 A for continuous operation
• 10 A not recommended for more than 2 min
  
  

Capacity Recording:

• 0–99999 Ah
• 0–99999 Wh
  
  

CPU:

• ARM M4F 240 MHz, 32-bit high-speed, with FPU hardware acceleration
  
  

Display:

• 1.54-inch color IPS LCD, 240×240 resolution, wide viewing angle
  
  

Sensors:

• 3-axis gravity sensor (for auto screen rotation)
  
  

Core ADC:

• Independent 16-bit ADC chip (INA226: 36 V, INA237: 48 V)
• On-chip high-speed ADC: 2 MHz
• Low-resistance shunt resistor (high-side sampling) with anti-common-ground interference
  
  

Interfaces:

• 24P USB-C male/female pass-through
• External sensor: NTC temperature probe -20 °C to +120 °C (via special Type-C interface)
  
  

Storage & Firmware:

• EEPROM with wear leveling
• Firmware upgrade: USB HID (driver-free, via dedicated USB-C HID interface)
• PC connection for curve plotting: HID software (USB-C HID, driver-free)
  
  

Identification:

• VIP Code: unique serial number
  
  

High-Speed Waveform Sampling:

• Up to 2 MHz
• Ripple analysis: simultaneously display frequency data and ripple values
  
  

Dimensions:

• Approx. 36.0 × 33.7 × 9.3 mm (excluding USB-C male connector)
  
  

NOTE：The software prompts that the runtime library is missing. Please install the .NET Core runtime first.
Runtime library download (win7, win10, win11 32/64 bit common) install x86, don't install 64

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The system is continuously updated.
Images and descriptions may differ from the actual product; the actual product shall prevail.


Press “+” to activate the PD charger and turn on the screen.
“Warning: Do NOT power on by pressing the OK button (detection or fast-charging trigger may cause the screen to go black).”

K2 Button & PD Operation Guide

1. K2 Pass-Through Mode

• Directly connecting a PD charger to the TYPE-C port will not light the screen.
• Press the “+” button to activate PD and light the screen.
  
  

2. K2 Male Port → Charger

• Press the lightning button to enable PD 5V output.
  
  

3. K2 Female Port → Charger via Original Cable

• Press and hold the lightning button to activate PD 5V output.
• If no response, flip the cable, reconnect, and long-press the lightning button again.
  
  

• PD protocol detection and triggering (including MIPPS) only work when the lightning button lights the screen.
  
  

4. Notes & Tips

• Some chargers require 10–15 seconds of power-off to restore output or fast-charging.
• If unresponsive, long-press the lightning button multiple times to discharge the charger.
• Pressing OK to light the screen disables PD measurement, because K2 has no battery or physical switch. PD requires the lightning button to activate the internal electronic switch.
• Modified chargers (e.g., Xiaomi Type-A mods) may output 5V immediately. To verify PD: press and hold the lightning button before connecting the AC cable and check the protocol screen. Flip the cable if no PD data appears.
• Always use the original PD/data cable with Emark when measuring or triggering protocols.
  
  

K2 Button Functions

• BACK: Return / Exit
• OK: Confirm / Execute / Save / Enter
• +: Switch screen / Adjust / Increment
• -: Switch screen / Adjust / Decrement
  
  

Tips – PD Observation for Modified Type-A Chargers

• Some modified Type-A PD chargers (e.g., Xiaomi, VIVO) output 5 V immediately upon insertion, without PDO broadcast.
• Inserting K2 will light the screen but show no PD information, making it impossible to determine CC orientation.
• Solution: Press and hold the lightning button while inserting the modified AC cable. If PDO data appears, the orientation is correct.
  
  

DFU Firmware Upgrade Mode

• Press and hold the “-” / DFU button while powering on to enter firmware upgrade mode.
  
  

Current Measurement Notes

• If measuring current from the female port input → male port output, K2 will detect its own operating current.
• USB meter devices typically draw tens of mA. To eliminate this effect, either:
  
  
  • Use male port input → female port output, or
  • Power K2 from the HID 5 V port.
    
    
  
  

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K2 Main Interface
P1: Large-font Current and Voltage Display Interface


P2: Measurement Interface / Capacity Statistics Interface


P3: High-Speed Ripple Waveform


P4: Function Menu

Note: The screen-off interface is disabled by default and can be enabled in the settings menu.

Press KEY+ / KEY- to switch screens forward/backward.

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P1 Main Interface

P1: Large-font display of Voltage, Current, and Power

P1 Interface: Voltage, Current, Power, and Current Direction

• Short press KEY+ / KEY- to switch screens forward/backward.
  
  

CC1: Currently triggered CC line of the USB meter.

• For standard 5 V chargers without PD, CC will be displayed.
• Many non-PD chargers may affect CC voltage and trigger CC1 or CC2 display—this is normal.
  
  

D+ / D-: Voltage on the two USB 2.0 communication lines, in volts (V).

Title Bar Icons:

• Right arrow: Gravity sensor enabled (can be disabled in P4 menu to switch manually).
• Computer icon: HID connection status.
  
  

Left Side: NTC – Display area for external temperature probe.

• Free DIY temperature probe tutorial available at the end of this webpage.
  
  

Screen Controls:

• Short press BACK to lock/unlock manual screen rotation.
• In lock mode, long press BACK to manually change screen orientation.
• Short press OK to pop up quick PDO list (non-PD chargers will not display info).
• Long press OK to switch screen refresh rate: selectable 1, 2, 5, or 10 FPS.
  
  

Oversampling Algorithm: Leveraging the 16-bit independent ADC chip, K2 performs signal oversampling to effectively improve signal acquisition resolution.

However, due to the uncertainty of signal noise, the standard resolution for K2 series is 0.0001 V and 0.0001 A. Values beyond four decimal places are calculated using the oversampling algorithm and may not be accurate—for reference only.

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K2 Special Feature: Quick PDO / Quick RDO Technical Demonstration

1 Main Interface: Quick PDO / RDO Brief Info Box

PD3.1 140W:

• PD3.1 indicates K2 has captured the real PD communication.
• 140W is the maximum PD broadcast power provided by the charger.
• Current K2 rule: regardless of SPR, EPR, PPS, or AVS, the maximum value among them is shown.
  
  

Second Line – FIX / PPS / AVS:

• FIX: The phone is currently requesting the 5th PD profile for charging; fixed voltage level.
• PPS: Continuously adjustable voltage within the SPR range.
• AVS: Continuously adjustable voltage within the EPR range.
• 140W: The actual power value currently requested by the phone.
  
  

Third Line – 28.00V 5.00A:

• Shows the voltage and current requested by the phone for charging.
• Note: The phone requesting this voltage/current profile does not guarantee charging at exactly this value.
• Actual charging voltage/current is generally lower than the requested numbers.
  
  

K2 Version 2.0 and above introduces multi-protocol passive monitoring.

• Supports listening to PD ID broadcasts from multiple well-known domestic and international charger brands.
  
  

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Quick PDO:
When a PD-enabled charger or power bank is connected to K2,
pressing the OK button in this interface allows you to quickly view the PD charger’s broadcast information.

• Quick PDO only displays the PD broadcast list and does not trigger high voltage.
• Since it does not change the voltage, PD data can be read safely and quickly.
  
  

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Quick PDO / RDO Detailed List:
When a phone is charging via PD, the brief info box may not show complete information.

• Press the OK button to display the detailed PD broadcast and charging request list.
  
  

Color Indicators:

• Green: The phone has requested the 3rd PD profile from the charger.
• Yellow (RDO): The phone’s currently requested voltage and current.
  
  

Notes:

• The phone’s requested voltage/current may not match the PDO broadcast exactly.
• The actual charging voltage/current may be higher, equal to, or lower than the requested values.
  
  
  • Example: The phone requests PPS 11 V 3 A, but actual charging could be 12 V 4 A. This is normal.
    
    

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Quick-Charging Protocol Assisted Estimation: “Fake Protocol” Introduction

Note: The fast-charging protocol shown as PROTOCOL is estimated based on the D+ and D– voltage levels and the charging voltage/current.

• It does not represent the actual fast-charging communication protocol being used by the phone or charger.
  
  

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Fast-Charging Protocol Real-Time Capture: Integrates Quick-Charging UFCS and VIVO (VFC)

K2 supports real-time capture of UFCS and VIVO (VFC) fast-charging protocols. It can decode charging data from both protocols in real time, displaying current voltage and current information.

• UFCS: Green indicates data packets are being captured; red indicates communication has paused.
• Note: After UFCS or VFC handshake, if the device stops communication but maintains the high-voltage profile, this is normal. This is commonly seen with power banks.
  
  
  • Example: A power bank requesting a fixed 11 V 4 A profile may stop communication, turning UFCS red.
    
    
  
  

Why does a 100 W charger show only 65 W on this interface when plugged directly into K2?

• The main interface performs passive PD listening and does not actively trigger charger PD profiles.
• Some protocol chips, if not triggered, will broadcast only low power.
  
  
  • Example: A 100 W (20 V 5 A) charger may only broadcast 65 W (20 V 3.25 A).
    
    
• To measure the full 100 W, enter the PD trigger interface for active testing.
• Currents above 3 A / 3.25 A generally require an Emark-equipped data cable. K2’s virtual Emark is not fully powered, so 5 A measurements require a proper Emark cable.
  
  

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P2 Capacity Statistics Interface

P2 Interface: Capacity Statistics

Title Bar:

• REC > 0.08 A: Data recording only starts when current exceeds this threshold. Most phones draw tens to over 100 mA of standby current after full charge, so a threshold is needed to accurately record capacity. Users can adjust this value by observing their phone’s standby current 30 minutes after full charge.
• Right side “1”: Indicates data is being recorded in the first storage slot. Short press BACK to switch to the second slot.
• Circular marker: Blinking indicates active recording.
  
  

Two Storage Slots:

• Designed to allow users to record charging and discharging capacities separately, useful for calculating conversion efficiency.
  
  

Metrics:

• Ah: Charging capacity
• Wh: Charging energy
• Left-side time: Duration of current offline recording for the selected slot
  
  

Controls:

• Long press OK to clear capacity data.
  
  

Storage Notes:

• K2 uses conventional EEPROM for offline capacity recording, not ultra-high-cycle ferroelectric storage like C5.
• Most of K2’s independent storage is allocated for wear-leveling algorithms.
• Remaining AVG and MAX values do not have enough redundant space for wear-leveling.
• K2 provides a workaround: power-off memory for MAX and AVG data. Short press OK to record, with a lifespan of over 1 million cycles.
  
  

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P3 Ripple Detection

P3: Ripple Detection Interface

• 2 M: Sampling frequency
• 100 kHz: Auto-tracked frequency value
• K2 features single-frequency tracking technology.
  
  

The black triangle icon with an orange cursor below the ripple waveform indicates auto-frequency lock.

• K2 can automatically track, lock, and calculate the waveform with the strongest spectral intensity and display its operating frequency.
  
  

Curves:

• Curve 1 (white): Actual ripple waveform
• Curve 2 (blue): Spectrum analysis
  
  

Ripple Curve: Reflects the amplitude of charger ripple (smaller is better).
Spectrum Curve: Reflects the frequency characteristics of the charger’s entire topology.

• From the spectrum curve, you can observe the charger’s switching frequency distribution:
  • Standard low-power QR flyback chargers: tens of kHz
  • High-frequency GaN chargers (e.g., AHB): over 100 kHz
    
    
• For chargers with secondary buck output: multiple strong peaks may appear in the spectrum.
  
  

Vpp: Current measured ripple value

• Typical chargers can maintain ripple below 200 mV.
  
  

Ripple Measurement Method:

• K2 must be placed close to the charger, directly connected.
• Use a data cable over 1 m to connect K2 to the trigger/load.
• Must use a professional commercial load for testing.
• Ripple data is typically measured at 20%, 50%, and 100% load.
  
  

Note: Using a phone or power bank as the load, or testing no-load, does not measure actual ripple.

Controls:

• Short press OK to switch sampling rates: 500 kHz, 1 MHz, 2 MHz.
• For standard chargers, 2 MHz sampling rate is recommended.
  
  

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P4 Tools menu.

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K2 Firmware Upgrade Method

Connect the HID port to a computer using a USB-C data cable.


First, press and hold the "DFU / -" button, then connect the USB-C port to the HID communication port.

When the DFU prompt appears on the screen, release the "DFU / -" button.



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DIY Type-C external temperature probe
1. Connect the TYPE-C connector’s GND to either SBU1 or SBU2.
2. The NTC sensor wires are not polarity-sensitive.

NTC specification: 10kΩ (±2%) @25°C, B=3435