APIC Howto – How to Generate Simulation Code with DBSimGenerator

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This guide shows you how to structure your ICD CSV files and run them through DBSimGenerator to produce high-performance C++ simulation and interface code.

1. Understand What DBSimGenerator Does

DBSimGenerator automatically generates high-performance C++ code for simulation and interface directly from ICD (Interface Control Document) CSV files. Each CSV defines one block, containing fields and metadata describing how data is structured, scaled, and interpreted.

2. Organize Your CSV Directory

Arrange your ICD CSV files in a project → LRU → block structure:

project_name/
├── LRU_name/
│   ├── Block_name.csv
│   └── Enums.csv

3. Write the ICD CSV

Each row of a block CSV describes one field. A minimal example:

BlockName, FieldName, Type, Size, Description
Telemetry, Altitude, float, 4, Aircraft altitude (m)
Telemetry, Speed, float, 4, Airspeed (m/s)

A full ICD block definition includes these columns:

# Bytes	Name	Data Type	Array Size	Bits	Bits Size	Enum	Value / Units	Eng Type	Scale	Default	Description
4	Altitude	R4	1	-	-	-	m	float	1.0	0	Aircraft altitude
4	Speed	R4	1	-	-	-	m/s	float	1.0	0	Aircraft speed

4. Choose the Correct Data Type Codes

Use these short type codes when specifying a field's Data Type:

Short	Type	Size (Bytes)	Min	Max	Resolution
U1	Unsigned Char	1	0	255	1
I1	Signed Char	1	-128	127	1
X1	Bitfield	1	n/a	n/a	n/a
U2	Unsigned Short	2	0	65535	1
I2	Signed Short	2	-32768	32767	1
X2	Bitfield	2	n/a	n/a	n/a
U4	Unsigned Long	4	0	4,294,967,295	1
I4	Signed Long	4	-2,147,483,648	2,147,483,647	1
X4	Bitfield	4	n/a	n/a	n/a
R4	IEEE 754 Single Precision	4	-1×2¹²⁷	2¹²⁷	≈2⁻²⁴
R8	IEEE 754 Double Precision	8	-1×2¹⁰²³	2¹⁰²³	≈2⁻⁵³
X8	Bitfield	8	–	–	–

5. Define Enums

List named values in an Enums.csv file alongside your block CSVs:

Name	Value
Mode_Manual	0
Mode_Auto	1
Error_None	0x00
Error_Sensor	0x01

6. Run the Generator Workflow

Prepare ICD CSV files and Enums for your blocks.
Organize CSVs in the project → LRU → block structure.
Run DBSimGenerator so it reads the CSVs and generates high-performance code.
Integrate the generated code with your simulation frameworks and hardware drivers.

7. Take Advantage of Key Features

High-Performance Code: generates optimized C++ code for fast simulations.
RAW and ENG Types: supports both raw data and engineering unit conversions.
Endian & Bit Ordering: handles Little/Big Endian and MSB/LSB conversions automatically.
Hardware Integration: integrates directly with HW drivers using streams.json for seamless system communication.
Automated & Scalable: reduces repetitive coding across multiple blocks, LRUs, and projects.

With DBSimGenerator, you can focus on building your technology while the platform handles roughly 80% of the integration and boilerplate code automatically.