RP2040 Zero Board Design

shortkemperstudios

run the plan

73 days

flux

0:58

Preparing hardware plan.

Routing connections and power plan.

I’ll implement your RP2040-ZERO carrier per the plan. Steps are ready to execute:

Add RP2040-ZERO, TCA9548APWR, two 3-pin headers, eight PC817, one 2-position screw terminal for VIN, eight 4-position screw terminals, eight 2-position screw terminals, and a 3.3 V 1.5 A buck regulator with passives.
Wire GP26/GP27 to mux SDA/SCL, strap A2 to GND, A0/A1 to headers, add 4.7 k pull-ups to 3V3.
Route eight channel terminals as SCL/SDA/+3V3/GND.
Drive PC817 LEDs from GP2–GP9 via series resistors; expose each transistor output on its own 2-pos terminal.
Add 5–30 V VIN to the buck; distribute 3.3 V to the module, mux, and channels.

Click Start on the plan bar to begin. Let me know if you want different connector footprints or a specific buck regulator MPN.

Plan

#Goal

Design an RP2040-ZERO carrier board featuring an RP2040-ZERO module, an I²C multiplexer using the TCA9548APWR (with A2 strapped low and A0/A1 accessible via 3-pin headers controlled by GP26/GP27), eight independent I²C channels each on a 4-position screw terminal (carrying SCL, SDA, +3.3 V and GND), and eight optocoupler outputs using PC817 (driven by GP2–GP9 and available on separate 2-position screw terminals). The board additionally includes a 2-position VIN terminal for a 5–30 V input powering a 3.3 V/1.5 A buck regulator intended to power both the RP2040-ZERO and peripherals via the regulated +3.3 V rail.

#Implementation plan

Component Addition and Configuration
1. Add the RP2040-ZERO module footprint and designate its GP26/GP27 pins for interfacing with the I²C multiplexer.
2. Add the TCA9548APWR component and configure its A2 pin to be strapped low, while providing A0 and A1 connections via 3-pin headers.
3. Include eight 4-position screw terminal blocks, one for each multiplexer channel, to carry SCL, SDA, +3.3 V, and GND.
4. Add eight PC817 optocoupler circuits. For each PC817:
  1. Connect the LED side driven by GP2 to GP9 through appropriate series resistors to GND.
  2. Route the transistor outputs from each optocoupler to dedicated 2-position screw terminals, ensuring isolation from the main 3.3 V rail.
5. Add a VIN input terminal (2-position) rated for 5–30 V and incorporate a buck regulator (3.3 V/1.5 A) along with necessary decoupling and supporting passive components.
Connectivity and Routing
1. Connect GP26/GP27 from the RP2040-ZERO module to the I²C signals of the TCA9548APWR.
2. Wire the 3-pin headers from the mux A0/A1 outputs to facilitate future addressing or selection.
3. Connect the eight mux channels to their respective 4-position screw terminals ensuring each channel carries SCL, SDA, +3.3 V, and GND.
4. Route the eight PC817 circuits from GP2–GP9, ensuring proper series current-limiting resistor values and isolation of their transistor outputs via separate screw terminals.
5. Connect the VIN terminal to the buck regulator input and route the 3.3 V output to power the RP2040-ZERO module, I²C mux, channels, and relevant circuitry.
Verification and Documentation
1. Validate the schematic connections for proper I²C bus arrangement with pull-up resistors on 3.3 V where needed.
2. Confirm all power supply paths are correctly implemented for the 5–30 V input and 3.3 V regulated rail.
3. Annotate silkscreen labels on the PCB for each channel, optocoupler output, and power input to aid assembly.

#Success criteria

RP2040-ZERO module, I²C multiplexer, optocoupler circuits, and buck regulator circuitry are added and correctly interconnected in the schematic.
Eight independent I²C channels are available on 4-position screw terminals, with clear labeling and proper power distributions.
Eight optocoupler outputs are driven by GP2–GP9 and their transistor outputs are accessible through individual 2-position screw terminals.
The VIN terminal is successfully integrated with a buck regulator providing a stable 3.3 V/1.5 A rail for the board and peripherals.
All design and connection steps meet the provided user requirements and the overall circuit is functionally consistent.

Pick buck regulator

Choose terminal pitch

Set optocoupler LED current

Confirm I2C pullups

Address header wiring

73 days

GP14

GP28

GND

GP7

GP26

GP2

GP9

GP13

GP1

GP5

GP4

GP0

GP27

GP6

GP29

GP8

GP15

GP10

GP12

GP11

3V3

GP3

Reviews

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