Board Refactor Plan

1:34

Following system rules for planning.

Clarifying tool usage for planning.

Planning queries and project guidelines.

Clarifying formatting and tool use.

Accessing knowledge base.

Creating a detailed execution plan.

I’ve built a plan to refactor your board to LoRa‑E5 only with solar LiFePO4 VSYS, SWD, and SMD edge pads, preserving RF to U4 → J2.

Cleanup & RF

Remove legacy/THT power/IO; keep U4/J2. Clear orphans. Define VSYS (set net types/voltages).

Solar LiFePO4 → VSYS

Add Solar+/Solar− and Batt+/Batt− pads.
PFET ideal‑diode reverse protection + OVP on solar input.
LiFePO4 charger capped at 50 mA; power‑path to VSYS; charge/protect indicators.

Rails from VSYS

Low‑Iq 3.3 V LDO with proper decoupling; verify dropout vs LiFePO4 min voltage (include peaks).
5 V boost 30 mA cont / 40 mA peak, with in/out caps and 5V_OUT pad.

Debug & I/O pads

Tag‑Connect TC2030 SWD: SWDIO/PA13, SWCLK/PA14, NRST (pull‑up), optional SWO/PB3, 3V3, GND.
Castellated SMD 2.54 mm pads:
- I2C SDA/SCL with 4.7 kΩ pull‑ups to 3V3; note maximum 400 pF bus capacitance.
- UART pads on PA2/PA3.
- Two one‑wire pads on PB13/PB15 with 2‑pad jumpers selecting 3.3 V (default) or 5 V pull‑ups.
- Adjacent 3V3/5V/GND pads.

Layout & finalize

Compact square outline, U4 centered, blue soldermask; keep power away from RF; preserve 50‑ohm feed to J2.
Replace generics with real MPNs; run ERC/DRC and fix; update description/BOM.

Let me know if you want any tweaks; otherwise click Start on the plan bar to execute.

Plan

#Goal

Refactor the Green Dot 2040E5 board into a LoRa‑E5 (STM32WLE5JC)-only board, adding a low‑power solar LiFePO4 subsystem to generate a well-regulated VSYS power rail, a low‑Iq 3.3 V LDO output, and a 5 V boost output. The design must include Tag‑Connect TC2030 SWD and SMD 2.54 mm castellated edge pads for I2C (with 4.7 kΩ pull‑ups and a 400 pF bus capacitance note), UART (PA2/PA3), and two one‑wire pads (PB13/PB15, with selectable pull‑ups via 2‑pad jumpers: default 3.3 V and optional 5 V), while preserving the RF connection from U4:RFIO to J2. The board should be a compact, square, blue PCB with pads‑only I/O.

#Implementation plan

Clean up and preserve relevant legacy connections
1. Remove legacy/THT power and I/O blocks.
2. Preserve U4 (LoRa‑E5 / STM32WLE5JC) and ensure the RF net (U4:RFIO) remains connected to J2 (IPEX RF).
3. Define VSYS with appropriate net types and voltage levels in ERC.
Implement the solar LiFePO4 power subsystem on VSYS
1. Add SMD edge pads for Solar+/Solar− and Batt+/Batt− connections.
2. Implement PFET reverse protection as an ideal diode along with over-voltage protection (OVP) on the solar input.
3. Integrate a LiFePO4 charger limited to 50 mA capable of powering VSYS, and include charge and protection indicator signals.
Develop voltage rails from VSYS
1. Add a low‑Iq 3.3 V LDO with proper decoupling, ensuring the dropout voltage matches the LiFePO4 minimum.
2. Implement a 5 V boost converter rated for 30 mA continuous and 40 mA peak, with required input/output capacitors and an exposed 5V_OUT pad.
Add debug and I/O pads
1. Place the Tag‑Connect TC2030 SWD connector, connecting it to SWD signals (SWDIO on PA13, SWCLK on PA14, NRST with pull‑up, and optional SWO/PB3), and provide access to 3V3 and GND.
2. Add SMD 2.54 mm castellated edge pads for the following interfaces:
  1. I2C SDA and SCL, with 4.7 kΩ pull‑ups to 3V3 (note the bus capacitance must not exceed 400 pF).
  2. UART on PA2 and PA3.
  3. Two one‑wire interfaces on PB13 and PB15, with 2‑pad jumpers allowing selection between 3.3 V (default) or 5 V pull‑ups.
3. Include adjacent breakout pads for 3V3, 5V, and GND connections.
Finalize the PCB layout
1. Configure the board as a compact square with a blue soldermask.
2. Position U4 (LoRa‑E5 module) centrally, and route power away from the RF paths.
3. Ensure a 50‑ohm controlled impedance feed from U4:RFIO to J2 remains intact.
4. Replace any generic parts with specific MPNs as necessary.
5. Run ERC/DRC and resolve any issues, and update the project description and BOM accordingly.

#Success criteria

The schematic is complete with all required subsystems fully wired and meeting the specified power rail and I/O configurations.
The RF net from U4:RFIO to J2 is preserved without modification.
The solar LiFePO4 subsystem with its protections and charging capability (50 mA cap) is correctly implemented and feeds VSYS.
The 3.3 V LDO and 5 V boost converter outputs are correctly defined and meet target current specifications.
Debug, I2C, UART, and one‑wire pads are placed and function with the required electrical parameters, and the board layout is a compact square with blue soldermask and pads‑only access.

Pick charger IC

Select 3.3V LDO

Choose 5V boost

Flux net settings

I2C pull-up sizing

C11

Capacitance

4u7 F

Capacitance

10uF

Capacitance

4u7 F

+3V3

Capacitance

10uF

Capacitance

100nF

Not Recommended for New Designs

Capacitance

68pF

VSOLAR

VBAT

+3V3

VBAT

Capacitance

100nF

+3V3

VUSB

Capacitance

100nF

Capacitance

10uF

U4 PA14 - U5 4

U4 PB3 - U5 5

NRST

PIO2

SDA

U4 PB7 - R20 P1

U4 PA13 - U5 2

+3V3

U4 PB15 - R12 P1

SCL

NRST

PIO1

+3V3

U9 VBAT1 - U10 VIN

L2 P1 - IC4 SW

Resistance

20kΩ

Resistance

2kΩ

Resistance

15kΩ

Resistance

1k5 Ω

R10

Resistance

22 Ω

Resistance

4k7 Ω

Resistance

68kΩ

Resistance

6k8 Ω

Inductance

2u2 H

Reviews

Ground
A common return path for electric current. Commonly known as ground.
jharwinbarrozo
20.5M
Net Portal
Wirelessly connects nets on schematic. Used to organize schematics and separate functional blocks. To wirelessly connect net portals, give them same designator. #portal
jharwinbarrozo
43.0M
Power Net Portal
Wirelessly connects power nets on schematic. Identical to the net portal, but with a power symbol. Used to organize schematics and separate functional blocks. To wirelessly connect power net portals, give them the same designator. #portal #power
jharwinbarrozo
11.4M
Generic Resistor
A generic fixed resistor ideal for rapid circuit topology development. Its footprint automatically adapts based on the selected package case code—supporting 0402, 0603, 0805, 1203, and many other standard SMD packages, as well as axial horizontal and vertical configurations. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard resistor values: 1.0 ohm, 10 ohm, 100 ohm, 1.0k ohm, 10k ohm, 100k ohm, 1.0M ohm 1.1 ohm, 11 ohm, 110 ohm, 1.1k ohm, 11k ohm, 110k ohm, 1.1M ohm 1.2 ohm, 12 ohm, 120 ohm, 1.2k ohm, 12k ohm, 120k ohm, 1.2M ohm 1.3 ohm, 13 ohm, 130 ohm, 1.3k ohm, 13k ohm, 130k ohm, 1.3M ohm 1.5 ohm, 15 ohm, 150 ohm, 1.5k ohm, 15k ohm, 150k ohm, 1.5M ohm 1.6 ohm, 16 ohm, 160 ohm, 1.6k ohm, 16k ohm, 160k ohm, 1.6M ohm 1.8 ohm, 18 ohm, 180 ohm, 1.8K ohm, 18k ohm, 180k ohm, 1.8M ohm 2.0 ohm, 20 ohm, 200 ohm, 2.0k ohm, 20k ohm, 200k ohm, 2.0M ohm 2.2 ohm, 22 ohm, 220 ohm, 2.2k ohm, 22k ohm, 220k ohm, 2.2M ohm 2.4 ohm, 24 ohm, 240 ohm, 2.4k ohm, 24k ohm, 240k ohm, 2.4M ohm 2.7 ohm, 27 ohm, 270 ohm, 2.7k ohm, 27k ohm, 270k ohm, 2.7M ohm 3.0 ohm, 30 ohm, 300 ohm, 3.0K ohm, 30K ohm, 300K ohm, 3.0M ohm 3.3 ohm, 33 ohm, 330 ohm, 3.3k ohm, 33k ohm, 330k ohm, 3.3M ohm 3.6 ohm, 36 ohm, 360 ohm, 3.6k ohm, 36k ohm, 360k ohm, 3.6M ohm 3.9 ohm, 39 ohm, 390 ohm, 3.9k ohm, 39k ohm, 390k ohm, 3.9M ohm 4.3 ohm, 43 ohm, 430 ohm, 4.3k ohm, 43K ohm, 430K ohm, 4.3M ohm 4.7 ohm, 47 ohm, 470 ohm, 4.7k ohm, 47k ohm, 470k ohm, 4.7M ohm 5.1 ohm, 51 ohm, 510 ohm, 5.1k ohm, 51k ohm, 510k ohm, 5.1M ohm 5.6 ohm, 56 ohm, 560 ohm, 5.6k ohm, 56k ohm, 560k ohm, 5.6M ohm 6.2 ohm, 62 ohm, 620 ohm, 6.2k ohm, 62K ohm, 620K ohm, 6.2M ohm 6.8 ohm, 68 ohm, 680 ohm, 6.8k ohm, 68k ohm, 680k ohm, 6.8M ohm 7.5 ohm, 75 ohm, 750 ohm, 7.5k ohm, 75k ohm, 750k ohm, 7.5M ohm 8.2 ohm, 82 ohm, 820 ohm, 8.2k ohm, 82k ohm, 820k ohm, 8.2M ohm 9.1 ohm, 91 ohm, 910 ohm, 9.1k ohm, 91k ohm, 910k ohm, 9.1M ohm #generics #CommonPartsLibrary
jharwinbarrozo
1.5M
Generic Capacitor
A generic fixed capacitor ideal for rapid circuit topology development. You can choose between polarized and non-polarized types, its symbol and the footprint will automatically adapt based on your selection. Supported options include standard SMD sizes for ceramic capacitors (e.g., 0402, 0603, 0805), SMD sizes for aluminum electrolytic capacitors, and through-hole footprints for polarized capacitors. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard capacitor values: 1.0pF, 10pF, 100pF, 1000pF, 0.01uF, 0.1uF, 1.0uF, 10uF, 100uF, 1000uF, 10000uF 1.1pF, 11pF, 110pF, 1100pF 1.2pF, 12pF, 120pF, 1200pF 1.3pF, 13pF, 130pF, 1300pF 1.5pF, 15pF, 150pF, 1500pF, 0.015uF, 0.15uF, 1.5uF, 15uF, 150uF, 1500uF 1.6pF, 16pF, 160pF, 1600pF 1.8pF, 18pF, 180pF, 1800pF 2.0pF, 20pF, 200pF, 2000pF 2.2pF, 22pF, 220pF, 2200pF, 0.022uF, 0.22uF, 2.2uF, 22uF, 220uF, 2200uF 2.4pF, 24pF, 240pF, 2400pF 2.7pF, 27pF, 270pF, 2700pF 3.0pF, 30pF, 300pF, 3000pF 3.3pF, 33pF, 330pF, 3300pF, 0.033uF, 0.33uF, 3.3uF, 33uF, 330uF, 3300uF 3.6pF, 36pF, 360pF, 3600pF 3.9pF, 39pF, 390pF, 3900pF 4.3pF, 43pF, 430pF, 4300pF 4.7pF, 47pF, 470pF, 4700pF, 0.047uF, 0.47uF, 4.7uF, 47uF, 470uF, 4700uF 5.1pF, 51pF, 510pF, 5100pF 5.6pF, 56pF, 560pF, 5600pF 6.2pF, 62pF, 620pF, 6200pF 6.8pF, 68pF, 680pF, 6800pF, 0.068uF, 0.68uF, 6.8uF, 68uF, 680uF, 6800uF 7.5pF, 75pF, 750pF, 7500pF 8.2pF, 82pF, 820pF, 8200pF 9.1pF, 91pF, 910pF, 9100pF #generics #CommonPartsLibrary
jharwinbarrozo
1.5M
Generic Inductor
A generic fixed inductor suitable for rapid circuit topology development. The footprint automatically adapts based on the selected package, supporting standard SMD sizes (e.g., 0402, 0603, 0805) as well as well-known inductor packages such as SDR1806, PA4320, SRN6028, and SRR1260. Standard inductor values: 1.0 nH, 10 nH, 100 nH, 1.0 µH, 10 µH, 100 µH, 1.0 mH 1.2 nH, 12 nH, 120 nH, 1.2 µH, 12 µH, 120 µH, 1.2 mH 1.5 nH, 15 nH, 150 nH, 1.5 µH, 15 µH, 150 µH, 1.5 mH 1.8 nH, 18 nH, 180 nH, 1.8 µH, 18 µH, 180 µH, 1.8 mH 2.2 nH, 22 nH, 220 nH, 2.2 µH, 22 µH, 220 µH, 2.2 mH 2.7 nH, 27 nH, 270 nH, 2.7 µH, 27 µH, 270 µH, 2.7 mH 3.3 nH, 33 nH, 330 nH, 3.3 µH, 33 µH, 330 µH, 3.3 mH 3.9 nH, 39 nH, 390 nH, 3.9 µH, 39 µH, 390 µH, 3.9 mH 4.7 nH, 47 nH, 470 nH, 4.7 µH, 47 µH, 470 µH, 4.7 mH 5.6 nH, 56 nH, 560 nH, 5.6 µH, 56 µH, 560 µH, 5.6 mH 6.8 nH, 68 nH, 680 nH, 6.8 µH, 68 µH, 680 µH, 6.8 mH 8.2 nH, 82 nH, 820 nH, 8.2 µH, 82 µH, 820 µH, 8.2 mH #generics #CommonPartsLibrary
jharwinbarrozo
15.8k
Terminal
An electrical connector acting as reusable interface to a conductor and creating a point where external circuits can be connected.
natarius
RMCF0805JT47K0
47 kOhms ±5% 0.125W, 1/8W Chip Resistor 0805 (2012 Metric) Automotive AEC-Q200 Thick Film #forLedBlink
jharwinbarrozo
1.2M
875105359001
10uF Capacitor Aluminum Polymer 20% 16V SMD 5x5.3mm #forLedBlink #commonpartslibrary #capacitor #aluminumpolymer #radialcan
jharwinbarrozo
1.2M
CTL1206FYW1T
Yellow 595nm LED Indication - Discrete 1.7V 1206 (3216 Metric) #forLedBlink
jharwinbarrozo
1.1M

Project Name

Description

The "Green Dot 2040E5" Board is a Node that interfaces RS485 Sensor probes and can log information to the cloud using LoRa Connectivity. It uses the XIAO RP2040 and the LoRa-E5 (STM32WLE5JC) modules from Seeed Studio to do its magic. It also has amazing power management capabilities (Solar charging, Battery protection, etc) that make it very useful for IoT applications #internetOfThings #smartHomeDevices #SeeedStudio #XIAO #LoRa #RP2040 #IoT

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor	Qty 1
Arrow	$13.98–$18.87
Digi-Key	$11.61–$14.77
LCSC	$12.72
Mouser	$18.56
TME	$0.80
Verical	$2.88–$10.77

Controls

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