README

iob-gpio

What is this repository for?

The IObundle GPIO is a RISC-V-based Peripheral written in Verilog, which users can download, modify, simulate and implement in FPGA or ASIC. This peripheral provides a General Purpose Input/Output interface with up to 32 inputs and 32 outputs. The tri-state output logic is supported via external tri-state buffers using the output enable interface of this peripheral.

This peripheral can be used as a verification tool of the OpenCryptoTester project.

Integrate in SoC

• Check out IOb-SoC-SUT

Usage

This peripheral has three 32-bit registers, one for each interface it provides. It has three interfaces with up to 32 ports:

• The input_ports input contains a set of ports, whose value can be read via gpio_get() function. This function returns a 32-bit value, where each bit corresponds to the value of the corresponding input port.
• The output_ports output contains a set of ports, whose value can be set via gpio_set(value) function. This function sets a 32-bit value, where each bit corresponds to the value of the corresponding output port.
• The output_enable output contains a set of ports, whose value can be set via gpio_set_output_enable(value) function. This function sets a 32-bit value, where each bit corresponds to the value of the corresponding output port.

The output_enable interface is used to trigger external tri-state buffers for the output_ports.

The number of ports is configurable via the GPIO_W Verilog parameter. If the GPIO_W parameter is less than 32, the most significant bits of the functions above will be ignored, as they will not match an existing port.

To instantiate the peripheral, add a dictionary describing the peripheral in the peripherals list of the blocks dictionary in the setup Python module of the system.

The iob_soc_sut_setup.py script of the IOb-SoC-SUT system, uses the following dictionary to instantiate a GPIO peripheral with the instance name GPIO0:

blocks = \
[
    # Other blocks here...

    {'name':'peripherals', 'descr':'peripheral modules', 'blocks': [
        {'name':'GPIO0', 'type':'GPIO', 'descr':'GPIO interface', 'params':{}},

        # Other peripheral instances here...
    ]},
]

Acknowledgement

The OpenCryptoTester project is funded through the NGI Assure Fund, a fund established by NLnet with financial support from the European Commission's Next Generation Internet programme, under the aegis of DG Communications Networks, Content and Technology under grant agreement No 957073.