ARCI (Amateur Radio Control Interface) PCB

This is the 1.1 revision of the ARCI PCB. It's also my first ever attempt at creating a board with a surface mount ESP32. I opted fo the ESP32-S3-WROOM-1U. This allowed me to not have to worry too much about having to deal with the cutout for the strip antenna. Since this board was to be mounted in an enclosure anyways, I wanted to be able to hook up an external antenna.

First revision had some mistakes such as D+ and D- from the UART chip being labeled wrong, along with a few other minor mistakes. Try to avoid using global labels everywhere in KiCad, it will fool you and the DRC. :P

The PCB is a 4 layer board that is designed to piggy back on the Sunton ESP32-8048S050C 5" display.

The firmware is called ARCI, which emulates a Kenwood TS‑590S. It's purpose is to serve as a CAT command router, interface and middleman between the radio (or RemoteRig) and a PC or control interface. In my specific case it's used as an interface between a RemoteRig RRC-1258 and my computer where the PCB is hooked up to buttons and encoders for VFO control, AF/RF gain, band selection etc.

KiCad projects

• ARCI/ARCI-SMT.kicad_pro - main SMT board project.
• ARCI/ARCI-Breakout.kicad_pro - breakout variant (this can be mostly ignored, I stopped working on this and made the SMT variant which was produced)
• Custom symbols/footprints live in ARCI/ARCI-eagle-import.kicad_sym and ARCI/Library.pretty/.

Hardware

• MCU: ESP32-S3 module
• USB: 2x USB-C with ESD protection; native USB D+/D- routed to the ESP32-S3 for CDC
• USB to UART is CH340C but I also experimented with CH340C (currently DNP)

ARCI and it's enclosure is effectively a "radio without the RF", meaning we need quite a bit of IO:

I2C stuff:

• TCA9548A is used for i2c muxing
• 2x TCA8418 keypad controller's (these are really handy IMO, simplifies the design a lot)
• Separate PCF8575 16‑bit I/O expander (primarily used as to hook up encoders)

Power:

• 3.3 V LDO (AMS1117-3.3) present on the ESP32-S3 module sheet.
• PCB stackup: 4-layer FR-4, 1.56 mm thickness.
• Board outline: ARCI-SMT is ~137.0 mm x 84.0 mm; ARCI-Breakout is ~136.7 mm x 84.0 mm; meant to piggy back a Sunton ESP32-8048S050C 5" display.

Board renders

ARCI-SMT

3D models (ARCI-SMT)

• STEP: docs/arci-smt.step
• GLB: docs/arci-smt.glb

Connectors & I/O highlights

• UART headers labeled for radio and display: UART1 (Radio) and UART2 (Display).
• Encoder connectors for VFO, multi-encoder, and generic encoder inputs.
• Switch matrix connectors for left/right key matrices and an F‑button matrix.
• I/O interrupt connector plus spare I/O headers for the PCF8575 and TCA8418.

Connector pinout (from ARCI/connectors.kicad_sch)

J3 - VFO Encoder

Pin	Net
1	NC/unnamed
2	NC/unnamed
3	NC/unnamed
4	NC/unnamed

J4 - Encoder Connector

Pin	Net
1	ENC 1 D1
2	ENC 1 B2
3	ENC 1 B1
4	ENC 1 A2
5	ENC 1 A1
6	ENC 2 A1
7	ENC 2 A2
8	ENC 2 B1
9	ENC 2 B2
10	ENC 2 D1

J5 - Multi Encoder Connector

Pin	Net
1	Multi-Knob CLK
2	Multi-Knob SW
3	GND
4	+3.3V
5	Multi-Knob DT
6	NC/unnamed

J6 - Right Switch Matrix Connector

Pin	Net
1	R1_Right
2	C1_Right
3	R2_Right
4	C2_Right
5	R3_Right
6	C3_Right
7	R4_Right
8	NC/unnamed
9	GND
10	+3.3V

J7 - Left Switch Matrix Connector

Pin	Net
1	R1_Left
2	C1_Left
3	R2_Left
4	C2_Left
5	R3_Left
6	+3.3V
7	R4_Left
8	NC/unnamed
9	GND
10	R5_Left

J8 - I/O Interrupts Connector

Pin	Net
1	TCA2_INT
2	PCF8575 INT
3	GND
4	+3.3V
5	TCA1_INT
6	NC/unnamed

J9 - F Button Switch Matrix Connector

Pin	Net
1	R2_F
2	R3_F3
3	GND
4	NC/unnamed
5	C2_F
6	NC/unnamed
7	C1_F
8	NC/unnamed

J10 - Conn_01x06

Pin	Net
1	GPIO36
2	GPIO37
3	GPIO39
4	GPI40
5	GND
6	NC/unnamed

J11 - UART1 (Radio)

Pin	Net
1	UART1 TX
2	UART1 RX
3	GND

J12 - Conn_01x05

Pin	Net
1	GPIO4
2	GPIO5
3	GPIO6
4	GPIO7
5	GND

J13 - UART2 (Display)

Pin	Net
1	UART2 TX
2	UART2 RX
3	GND

J14 - Conn_01x06

Pin	Net
1	GPIO46
2	GPIO9
3	GPIO10
4	GPIO8
5	GND
6	NC/unnamed

J15 - Conn_01x04

Pin	Net
1	GPIO48
2	GPIO47
3	GND
4	NC/unnamed

Notes

• Connector pinout tables reflect schematic net labels verbatim (for example, GPI40 appears as labeled).

License

GNU General Public License v3.0 or later