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Cyclic

tpcarlson·synth-diy·cyclic/cyclic.kicad_pcb

Cyclic PCB layout, top view — open source RP2040/RP2350 board by tpcarlson

About the Cyclic PCB

Cyclic is an open source RP2040/RP2350 PCB design by tpcarlson, published on GitHub. It is a 4-layer board measuring 241.2 × 160 mm, with 437 components from 40 distinct parts.

Its main chip is the RP2350_80QFN, from the RP2040/RP2350 family. Other key parts include the NCP1117-3.3_SOT223, 74AHCT1G125, MCP23S17_SO and 6N137. By type, the board carries 165 capacitors, 139 diodes, 50 resistors, 27 connectors, 20 ICs and 18 switches.

It belongs with the audio designs in this gallery.

From the project

Mostly Eurorack projects

Cyclic is a stand-alone, 8-channel, 16-step trigger sequencer. It has 8 clock inputs to allow for independent clocking of each channel, and 8 individual trigger outputs. Trigger inputs are normalled, so if you want to, you can clock Cyclic with just one trigger. Additionally, it has a pair of TRS-A MIDI ports for input and output.

Cyclic is designed to be driven externally and thrives on clocks that are a bit ... weird. Because Cyclic has no real concept of time, you can throw whatever wonky clocks you want at it and it'll do its best to keep advancing the clock. This goes all the way up to…

Cyclic, from the project README
From the project README

Main components on the Cyclic

NCP1117-3.3_SOT223RP2350_80QFN74AHCT1G125MCP23S17_SO6N137

Cyclic bill of materials (BOM)

437 components, 40 distinct parts.

QtyPartRefs
1
NCP1117-3.3_SOT223
U1
1
RP2350_80QFN
U2
9
74AHCT1G125
U3, U12, U13, U14, U15, U16, U17, U18 +1
8
MCP23S17_SO
U4, U5, U6, U7, U8, U9, U10, U11
1
6N137
U20
8
MMBT3904
Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8
1
ABM8-272-T3
Y1
1
USB_C_Receptacle_USB2.0_16P
J1
1
Conn_01x03
J2
1
Barrel_Jack
J3
2
AudioJack3
J4, J21
16
AudioJack2
J5, J6, J7, J8, J9, J10, J11, J12 +8
2
Conn_01x08_Pin
J22, J24
2
Conn_01x08_Socket
J23, J25
2
Conn_01x02_Pin
J26, J27
2
SW_Push
SW1, SW2
16
~
SW3, SW4, SW5, SW6, SW7, SW8, SW9, SW10 +8
8
TestPoint
TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8
2
ESD
D1, D2
1
1N4148W
D3
Show 20 more
QtyPartRefs
128
SK6812MINI-e (Reverse-mount)
D5, D6, D7, D8, D9, D10, D11, D12 +120
8
1N4148
D133, D134, D135, D136, D137, D138, D139, D140
1
3.3u
L1
4
4.7u
C1, C4, C7, C8
2
15p
C2, C3
11
10u
C5, C9, C21, C22, C40, C58, C76, C94 +3
148
100n
C6, C10, C11, C12, C13, C14, C15, C16 +140
2
5.1k
R1, R4
2
1k
R2, R3
1
33
R5
1
1k
R6
2
27
R7, R8
2
500R
R9, R10
17
10k
R11, R12, R13, R14, R15, R16, R17, R18 +9
8
100k
R19, R22, R25, R28, R31, R34, R37, R40
8
100R
R20, R23, R26, R29, R32, R35, R38, R41
2
1k
R43, R44
1
220R
R45
2
51R
R47, R48
2
51R
R49, R50

Cyclic design files

The KiCad project lives in the tpcarlson/synth-diy repository on GitHub; these links point at the commit this page was built from.

Cyclic: common questions

What microcontroller does the Cyclic use?

The Cyclic is built around the RP2350_80QFN, from the RP2040/RP2350 family.

How big is the Cyclic PCB?

The Cyclic measures 241.2 × 160 mm, has 4 copper layers and is 1.6 mm thick.

How many components are on the Cyclic?

437 components, from 40 distinct parts. The full bill of materials is listed on this page.

Where can I download the Cyclic design files?

From the tpcarlson/synth-diy repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the Cyclic design in my own project?

The repository has no license, so all rights stay with tpcarlson. Use it as a reference, and ask the author before reusing the design.

Can I test firmware for the Cyclic without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug RP2040/RP2350 firmware against it before you order a PCB.

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