GPIO Configuration for OpenFrame

A simple parameterized GPIO pad configuration wrapper for ChipFoundry Openframe projects.

Set the mode once, forget about pad details.

Quick Start

// GPIO as OUTPUT
CF_gpio_config #(.MODE(3'd4)) gpio_out_inst (
  .io_out(my_data_out),
  .io_in(),
  .io_oeb(),
  .gpio_zero(gpio_loopback_zero[5]),
  .gpio_one(gpio_loopback_one[5]),
  .gpio_in(gpio_in[5]),
  .gpio_dm({gpio_dm2[5], gpio_dm1[5], gpio_dm0[5]}),
  .gpio_inp_dis(gpio_inp_dis[5]),
  .gpio_oeb_out(gpio_oeb[5]),
  .gpio_out_val(gpio_out[5]),
  .gpio_analog_en(gpio_analog_en[5]),
  .gpio_analog_sel(gpio_analog_sel[5]),
  .gpio_analog_pol(gpio_analog_pol[5]),
  .gpio_ib_mode_sel(gpio_ib_mode_sel[5]),
  .gpio_vtrip_sel(gpio_vtrip_sel[5]),
  .gpio_slow_sel(gpio_slow_sel[5]),
  .gpio_holdover(gpio_holdover[5])
);

// GPIO as INPUT with pull-up
CF_gpio_config #(.MODE(3'd3)) gpio_in_inst (
  .io_out(),
  .io_in(my_data_in),
  .io_oeb(),
  .gpio_zero(gpio_loopback_zero[6]),
  .gpio_one(gpio_loopback_one[6]),
  .gpio_in(gpio_in[6]),
  // ... connect config outputs (including gpio_out_val for pull-up)
);

Modes

MODE	Name	gpio_dm	gpio_oeb_out	gpio_out_val	Description
0	ANALOG	000	1	0	Analog mode - disables input and output buffers
1	INPUT	001	1	0	Digital input, no pull resistor (floating)
2	INPUT_PD	111	0	0	Digital input with pull-down (~5kΩ)
3	INPUT_PU	111	0	1	Digital input with pull-up (~5kΩ)
4	OUTPUT	110	0	io_out	Digital output, push-pull driver
5	BIDIR	110	io_oeb	io_out	Bidirectional - direction controlled by io_oeb

Note: The gpio_out_val output handles both user data and pull-mode values automatically:

• For OUTPUT/BIDIR modes: passes through your io_out signal
• For INPUT_PD: drives 0 to activate weak pull-down
• For INPUT_PU: drives 1 to activate weak pull-up

Analog Note:

• For ANALOG: CF_gpio_config does not connect to the actual analog signal - it just configures the gpio. The direct pad connection is analog_io[N] or analog_noesd_io[N] of the openframe_project_wrapper.

3.3V Note:

• Any modes that drive io_in at 1.8V also have a 3.3V version of the signal available in openframe_project_wrapper as gpio_in_h[N].

User Interface

Signal	Direction	Description
io_out	input	Data to drive the pad (OUTPUT/BIDIR modes)
io_in	output	Data from the pad
io_oeb	input	Output enable bar (BIDIR: 0=drive, 1=hi-z)

Openframe Interface

Connect these to your openframe_project_wrapper signals:

Signal	Connect to
gpio_zero	gpio_loopback_zero[n]
gpio_one	gpio_loopback_one[n]
gpio_in	gpio_in[n]
gpio_dm[2:0]	{gpio_dm2[n], gpio_dm1[n], gpio_dm0[n]}
gpio_inp_dis	gpio_inp_dis[n]
gpio_oeb_out	gpio_oeb[n]
gpio_out_val	gpio_out[n]
gpio_analog_en	gpio_analog_en[n]
gpio_analog_sel	gpio_analog_sel[n]
gpio_analog_pol	gpio_analog_pol[n]
gpio_ib_mode_sel	gpio_ib_mode_sel[n]
gpio_vtrip_sel	gpio_vtrip_sel[n]
gpio_slow_sel	gpio_slow_sel[n]
gpio_holdover	gpio_holdover[n]

Files

CF_gpio_config/
  rtl/
    CF_gpio_config.v   # Main wrapper module
  docs/
    USAGE.md               # Detailed usage guide
    SIGNAL_MAPPING.md      # Mode-to-signal reference
  README.md                # This file
  LICENSE                  # Apache 2.0

License

Apache 2.0 - See LICENSE