I/O modules

AXO-006 — SSD1306 OLED carrier PMOD module

Catalog #6 in the AruviX output line, level L3 (I2C). Socketed carrier for the ubiquitous 0.96" SSD1306 128×64 I2C breakout — the bare OLED flex has no stock KiCad assets and the breakout is what every student already owns (same carrier pattern as sensor modules axs-021/axs-046).

Level L3 ERC clean DRC clean Fab package 8 components

3D render of the AXO-006 PCB — Rendered from the PCB layout. No physical board has been manufactured.

Circuit review & bench-test guide →

Components#

Every placed component, with the reason it is on the board. Extracted directly from the schematic, so this cannot drift from the design.

Ref	Value	What it does on this board	Part number	Footprint
`C1`	100nF 16V X7R	Decoupling at the OLED socket	`GRM188R71C104KA01D` Murata	`C_0603_1608Metric`
`C2`	10uF 10V X5R	Bulk for the breakout's charge-pump switching current	`GRM21BR61A106KE19L` Murata	`C_0805_2012Metric`
`J1`	PMOD PLUG 2x6	PMOD peripheral plug (Digilent spec 1.2)	not selected generic	`PinHeader_2x06_P2.54mm_Horizontal`
`J2`	SSD1306 OLED (GND/VCC/SCL/SDA)	0.96in SSD1306 I2C breakout socket: 1 GND, 2 VCC(3V3), 3 SCL, 4 SDA - VERIFY ORDER	not selected generic Datasheet ↗	`PinSocket_1x04_P2.54mm_Vertical`
`JP1`	SDA PULL-UP	Cut to remove the SDA pull-up when chaining modules	—	`SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm`
`JP2`	SCL PULL-UP	Cut to remove the SCL pull-up when chaining modules	—	`SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm`
`R1`	4.7k	I2C SDA pull-up	`RC0603FR-074K7L` Yageo Datasheet ↗	`R_0603_1608Metric`
`R2`	4.7k	I2C SCL pull-up	`RC0603FR-074K7L` Yageo Datasheet ↗	`R_0603_1608Metric`

Signals#

Net labels used in the schematic, which are also the names the HDL top level should use.

3V3 GND SCL SCL_PU SDA SDA_PU

Production status#

Schematic ERC	0 violations
PCB layout	complete
DRC	0 violations
Fab package	exported (24 gerbers + drill + CPL + BOM)
Fabricated	no — design stage only

Source: boards/io-modules/axo-006-oled

Catalog #6 in the AruviX output line (../README.md), level L3 (I2C). Socketed carrier for the ubiquitous 0.96" SSD1306 128×64 I2C breakout — the bare OLED flex has no stock KiCad assets and the breakout is what every student already owns (same carrier pattern as sensor modules axs-021/axs-046).

Status: schematic generated, ERC clean (0/0), netlist reviewed. PCB layout not started. Not released.

What it teaches#

The first graphic framebuffer: 1 KiB of display RAM the host owns. HDL ladder: I2C init-sequence ROM player → pixel writes → full framebuffer with font ROM (chargen). I2C address 0x3C on virtually all 0.96" breakouts (a 0x3D strap variant exists — scan the bus first).

Design#

J2 = 1×4 pin socket (Connector_PinSocket_2.54mm:PinSocket_1x04_P2.54mm_ Vertical), wired 1 GND, 2 VCC(3V3), 3 SCL, 4 SDA.
PIN-ORDER WARNING (also printed on the schematic, must go on silk): the market splits between GND-first and VCC-first breakouts, and reversed power kills the module instantly. Compare your breakout's silkscreen with the carrier silkscreen before plugging; if it differs, don't force it.
Runs from PMOD 3V3 (breakout's onboard charge pump makes the panel voltage; 20–30 mA typical draw is PMOD-safe).
Standard I2C module pattern: 4.7 kΩ pull-ups through cuttable JP1 (SDA) / JP2 (SCL) jumpers — most breakouts carry their own 10 k pull-ups, the parallel combination is still legal, and the jumpers let you shed ours when chaining.
100 nF + 10 µF at the socket (charge-pump switching current).

PMOD pin	1	2	3	4	5	6	7	8	9	10	11	12
Net	NC	NC	SCL	SDA	GND	3V3	NC	NC	SCL	SDA	GND	3V3

Regenerate#

python3 generate_design.py

Remaining for release#

[ ] PCB layout (socket orientation silk both ways), DRC, fab outputs
[ ] hdl/: I2C master reuse + SSD1306 init/framebuffer core, ECP5 demo
[ ] BOM export and availability check, design-review checklist