Goldfish

This article requires additional photographic illustration

The Goldfish is an open-hardware microcontroller board designed by Dr Derivative. It was designed to be backwards-compatible with the Pro Micro. It features a mid-mounted USB type C port and more I/O pins.

Differences to the Pro Micro

Changes

• The USB port is now USB type C, which is both through-hole and SMD mounted. It should be tougher and not as easily torn off as the USB micro B port on the original Pro Micro, but because it is mid-mounted: not be thicker.
• The silk-screened print on the board lists the actual ATmega32U4 port and bit numbers, not Arduino numbering. Only on the bottom.

Additions

• Five additional I/O pins are exposed on the short edge.

Omissions

• No LEDs. The PB0 pin has not become available for use though.
• It has no voltage regulator and runs only on +5V.

Revision history

Rev. 0

Initial design. Did not have a diode from VBUS to VCC, which was necessary for master/slave auto-detect in split keyboards.

Rev. A

Footprint of C6 was changed

Rev. B

Diode added for split keyboard compatibility.

Rev. C

The order of the pins on the short edge changed to match the Elite-C

Version 2

ESD protection and polyfuse, all 0603 resistors and capacitors, castellated edges, more common USB-C connector footprint

Pinout

Microcontroller side:

Arduino		AVR	↑					AVR	Arduino
			USB port
			(picture)
TX	D1	PD3						RAW (VBUS)
RX	D0	PD2						GND
GND								Reset
GND								Vcc (+5V)
SDA	D2	PD1						PF4	D21	A3
SCL	D3	PD0						PF5	D20	A2
A6	D4	PD4						PF6	D19	A1
	D5	PC6						PF7	D18	A0
A7	D6	PD7						PB1	D5	SCLK
	D7	PE6						PB3	D14	MISO
A8	D8	PB4						PB2	D16	MOSI
A9	D9	PB5						PB6	D10	A10
			PB7 (PB7)	PD5 (PD6)	PC7 (PC7)	PF1 (PF0)	PF0 (PF1)

• Internal pins: D+, D-
• Rev B short edge within parentheses

Availability

The design is open source.

Derivative boards

Goldfish V1:

• Alvaro — using 0603 components
• Comet — using a a HRO TYPE-C-31-M-12 connector
• Whale — using a Jing 918-418K2024S40000 connector
• Goldfish-clone-JLCPCB — Designed to meet JLPCB's assembly requirements

Stores

• Beekeeb
• Tokas (Comet)

See also

• Elite-C — similar features and layout but is thicker.

External links

• Geekhack — Goldfish - A super thin USB-C Pro Micro clone
• Github repository