March 2019, HDL Works announces the release and immediate availability of IO Checker 4.0,
the FPGA and PCB IO verification tool.

About IO Checker

IO Checker will verify that signal names used in the FPGA are connected to the appropriate signals on the PCB. Additionally it verifies the voltage values connected to the FPGA power and reference pins. IO Checker uses rules (based on regular expressions) to match the signals names in both the FPGA and PCB design environment. The rules can be generated automatically and be fine-tuned by the designer. The automated approach will often match 80% to 90% of all device pins.

The flexibility of IO Checker allows it to be used in any design flow and does not require any design methodology. The rules generator in combination with the sorted problem view allows engineers to validate a 1000+ pin device in half an hour.

What is new in IO Checker 4.0

Signal view

The HDL view has been transformed into the Signal view. The user can modify all properties of the signals (like name, range, direction, location constraint) and add or delete signals. The data in the Signal view can be:

The signals in this view can be edited by the user and than be used to: The new approach allows you to adjust / modify imported data before it is used.

CSV import

The HDL CSV import and FPGA CSV data import are replaced by a single CSV import that will import data into the Signal view. The import will merge the data found in the file with data already present in the Signal view. Signals already present in the view but not in the import are not removed. The dialog has a ‘Determine import settings‘ button to automatically determine the comment character, column separator and FPGA pin name.
CSV Import dialog
CSV Import dialog


The verification is now task driven instead of source driving. The new approach makes it easier to perform a specific verification task. The verification mode specified in the wizard will be used as the default mode during verification.

The individual verification tasks can also be started from the Verify menu.
Verification wizard
Verification wizard dialog

Matching rules

IO Checker matching rules
IO Checker matching rules

The matching rules dialog has an extra checkbox, that allows you to use the derived PCB signal name in the matching rules. This is very useful when signals are tied to ground using a resistor, and the direct signal name is a system generated name. In the example below pin AT14 is functionally connected ground (over a resistor). Using the checkbox ‘derived’ in the Rules dialog this can automatically be verified.

Use of derived netname
Use of derived netname (direct pulldown)

FPGA pin file processing

Several improvements were made to the pin file readers:


Extract vref pin data from the pin layout file.

Intel (Altera)

Support for default IO standard (STRATIX_DEVICE_IO_STANDARD) in the constraint file.


Unused signals in Xilinx are now reported in the pin view as <UNUSED> instead of using the pin functional name (like <IO_L11N_6>). This allows the rule engine to create rules for them.


Improved recognition of drive strength and slew rate.

Device Support

The following device families (or additional devices) have been added:

Availability and Pricing

IO Checker 4.0 is available now. Prices begin at € 750 or US$1,125. IO Checker can be downloaded and evaluated from the HDL Works website.

About HDL Works

HDL Works develops and markets high-performance, intuitive tools for complex HDL design across a wide spectrum of applications. HDL Works currently holds ConnTrace, EASE, HDL Companion and IO Checker in its product portfolio. Headquartered in Ede, The Netherlands, HDL Works is privately held.

HDL Works BV
Keperlaan 12
6716 BS Ede
The Netherlands

ConnTrace, EASE, HDL Companion, IO Checker and Scriptum are trademarks of HDL Works.

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