KCU Analog/Digital/Frequency Input Channel
KCU GEN1 / GEN2 provides three channel types: analog input (AI), digital input (DI / MSDI), and frequency input (FI), which respectively correspond to different signal forms of vehicle sensors.This article organizes the channel configuration, signal conditioning circuit and KopherSAR I/O abstract interface of each generation of KCU.
Summary
KCU series controller provides three input channel types corresponding to vehicle sensor signal forms:
- Analog Input (AI) — Continuous voltage measurements (e.g. pressure, temperature, pedal position).
- Digital Input (DI / MSDI Multi-Switch Detection Input) — binary switch signal (button, limit switch, relay status).
- Frequency Input (FI) — Pulse frequency measurement (rotation speed, vehicle speed, flow rate).
The number of channels varies by product: GEN1: 15 AI / 44 DI / 4 FI; GEN2 (Phase B): 20 AI / 22 DI / 4 FI; GEN2 Micro: 4 AI / 4 DI / 2 FI.All inputs are mapped to the application layer SWC through the KopherSAR I/O abstraction (Adc / Dio / Icu).
Technical Role
| Channel type | Signal form | Typical applications |
|---|---|---|
| Analog Input | Continuous voltage (0–5 V or 0–36 V range) | Oil pressure, water temperature, intake air temperature, throttle position, pedal sensor |
| Digital Input (MSDI) | Binary high/low position | Seat belt switch, brake light switch, gear switch, button |
| Frequency Input | Pulse signal | Wheel speed, engine speed, hydraulic pump pulse, flow meter |
KCU is equipped with a signal conditioning circuit on the AI/DI channel: voltage divider resistor, pull-up/pull-down resistor, series resistor, filter capacitor, etc., which can be configured according to the characteristics of the vehicle signal source.
Architecture
| Hierarchy | Role |
|---|---|
| Vehicle Sensor | Output original analog/digital/frequency signals. |
| Signal conditioning circuit | Voltage division, over-voltage protection, and noise filtering bring signals into the MCU’s safe range. |
| MCU built-in peripherals | ADC (AI), GPIO (DI), ICU/Timer (FI). |
| KopherSAR I/O abstract | Adc / Dio / Icu module, corresponding to ECU Pin through Port. |
| RTE | Pass input values to SWC. |
| Application SWC | Signal processing, control logic, diagnostic interpretation. |
Channel configuration (differences between generations)
| Channel | KCU GEN1 | KCU GEN2 (Phase B) | KCU GEN2 Micro |
|---|---|---|---|
| Analog Input | 15 | 20 | 4 |
| Digital Input (MSDI) | 44 | 22 | 4 |
| Frequency Input | 4 | 4 | 2 |
| AI range | 5 V and 36 V optional | Same | Same |
| AI default circuit | Pull Up / Pull Down / Series Res / Voltage Divider / Filter Cap (according to channel) | Same | Same |
The AI channel of GEN1 is divided into 5 V range and 36 V range for measuring different signal voltages.Each channel is preset with different pull-up/pull-down resistors, series resistors, voltage divider resistors and filter capacitors according to design requirements.
Key Capabilities
- Various AI preset circuit settings (5 V measurement range and 36 V measurement range), compatible with common sensor outputs in vehicles.
- The DI channel adopts MSDI (Multi-Switch Detection Input) architecture and has built-in debounce logic.
- FI channel supports multiple sensor types (Hall, inductive, passive electromagnetic).
- KopherSAR The I/O abstraction provides a standardized API to prevent the application layer from directly touching the ADC registers.
- Integrated with diagnostic module: channel short circuit, open circuit, out of range and other conditions can be recorded as DTC.
Engineering Inputs Required
| Input | Purpose |
|---|---|
| Sensor specification list | Signal voltage range, output impedance, power requirements. |
| Channel Assignment Table | Maps actual sensors to KCU AI/DI/FI Pins. |
| Signal conditioning requirements | Whether pull-up/pull-down, filtering, and protection voltage are required. |
| Sampling rate and accuracy | Configure ADC sampling frequency, resolution, and FI measurement range. |
| Diagnostic interpretation conditions | Out of range, Plausibility, Stuck and other fault interpretation rules. |
How KopherBit Supports This
- Basic software: KopherSAR provides Adc, Dio, Icu, Port modules and BSW configuration.
- Configuration Tool: KopherConfig Directly configure the ADC sampling group, Dio direction, and Icu measurement mode of each channel.
- Signal Conditioning: KCU The hardware has built-in a variety of preset circuits; customers can select the corresponding channel at the BOM stage according to the sensor type.
- Diagnosis: DEM can receive ADC out-of-range, DI stuck, FI loss and other events and convert them into DTC.
FAQ
Why are AI channels divided into 5 V and 36 V ranges?
The 5 V range is suitable for high measurement accuracy requirements and the signal source is a 5 V sensor in the car (such as some pressure and temperature sensors).The 36 V range is suitable for measuring vehicle power-related signals (such as battery voltage, 12 V signal chain) and has over-voltage protection.
What is the difference between MSDI and general GPIO?
MSDI multiplex digital input can centrally read multiple button/switch status on a single IC through internal multiplexing and low-speed sampling mechanism, and has debounce and ground short circuit detection.Compared to reading directly from GPIO, MSDI is more suitable for large-scale digital input scenarios.
What sensor types does the FI channel support?
Supports passive electromagnetic type (such as typical wheel speed sensor), active Hall Effect type (Hall Effect), passive inductive type, etc. Specific support depends on matching the KCU channel specification and sensor voltage/polarity.
Are channels reconfigurable?
HS_RunTimeModeCfg / LS_RunTimeModeCfg is for Demo purpose; the physical circuit of the AI / DI / FI channel is fixed at the hardware layer, but the BSW configuration (such as sampling rate, whether to enable, diagnostic interpretation) can be modified by KopherConfig.
What to do when the signal is out of range?
The KopherSAR Adc module can determine whether it exceeds the valid range after sampling, submit the event to DEM, record it as a DTC, and have the SWC apply security policies (adopt the last valid value, enter Failsafe mode, etc.).
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