3/21/2026 - Studied RP2040 datasheet pinouts thought about board design.

RP2040 Microcontroller Unit

I researched about RP2040 Microcontroller unit and learned about its specs, limitations and advantages.

Looked into pinouts and their purposes. As I learned, you get 30 multi-function GPIO pins, all running at 3.3V and 4 of those can double as analog inputs. The GP0 to GP22 pins handle digital input and output. For analog stuff, use GP26 through GP29. These work as 12-bit ADCs.

When it comes to communication, there are options:

• Two UARTs
• Two SPIs
• Two I2Cs
• Eight PIO state machines

There are 16 independent channels, so every GPIO can do PWM.

Inside, there’s an LDO on the chip that keeps the core running at 1.1V.It takes input anywhere from 1.8V to 3.3V and handles the conversion automatically.

Also learned how they are used based on Raspberry Pi Pico.## RP2040 Microcontroller Unit

I researched about RP2040 Microcontroller unit and learned about its specs, limitations and advantages.

Looked into pinouts and their purposes. As I learned, you get 30 multi-function GPIO pins, all running at 3.3V d 4 of those can double as analog inputs. The GP0 to GP22 pins handle digital input and output. For analog stuff, use GP26 through GP29. These work as 12-bit ADCs.

When it comes to communication, there are options:

• Two UARTs
• Two SPIs
• Two I2Cs
• Eight PIO state machines

There are 16 independent channels, so every GPIO can do PWM.

On the power side:

• VBUS for 5V input
• VSYS for anything from 1.8V to 5.5V
• A 3.3V output pin

For debugging and programming, the chip supports:

• USB 1.1 (both host and device modes)
• Serial Wire Debug port

Inside, there’s an LDO on the chip that keeps the core running at 1.1V.It takes input anywhere from 1.8V to 3.3V and handles the conversion automatically.

Also learned how they are used based on Raspberry Pi Pico and looked into micro python because that's the language I am familiar with.

RP-008307-DS-1-pico-datasheet
RP-008371-DS-1-rp2040-datasheetRP-008279-DS-1-hardware-design-with-rp2040

links referenced :
https://www.raspberrypi.com/documentation/microcontrollers/pico-series.html
https://docs.micropython.org/en/latest/library/rp2.html
https://www.circuitstate.com/news/rp2040-pico-all-new-microcontroller-and-development-board-from-raspberry-pi/

3/22/2026 12 PM - Started making schematics

I taken the RP2040 mcu and assigned global values based on the documentation and wired up usb-c port in the schematics also check voltage compatibility

3/22/2026 1:01 PM - determining the headers based on pico

I determined the header pins based on raspberry pi Pico and checked compatibility with my previous global values and assigned every pin in order so that I don't have confusion

3/22/2026 1:22 PM - Added capacitors, safety measures that are not present pico

added capacitors to voltage outputs of RP2040 and changes planed
Dual LEDs
USB Series Resistors
Extended Test Points
SWD Debug Connector
Power Decoupling Layout
Crystal Circuit
and changed the labels to look clean

new headers after changing the labels

simplified usb c part so that things can be categorized

3/23/2026 - decided on an eeprom module, implemented QSPI flash memory

added bootsel button and added Quad Serial Peripheral Interface and also implemented noise filtering with capacitors(C5)also checked if programming mode activation with bootsel button
also implemented Non-Volatile Ferroelectric RAM (F-RAM) storage circuit and I2C Communication Interface

3/24/2026 4 PM - Implementing filtering, power and crystal oscillator

I added filtering.power and crystal oscillator and also analog to digital verf that sums up the schematic part that i planed to do and I am going to move on to pcb design next

3/24/2026 5:07 PM - checked out pi pico dimensioning and created outline

after finishing the schematics I moved onto pcb design created outline and roughly placed parts on the boards outline and check whether routing will be easier
this is based on the original pico dimensioning

and this is the final schematicsschematics_devboard

3/24/2026 5:13 PM - routed bottom layer

I routed bottom layer first because I am to overwhelmed to route the main connections from mcu and these are slightly easier and also made drill holes and mounting points for type c port and also added vias for future connections I think I will do front side routing after homework is done I am felling pretty happy for what I done until now

3/24/2026 6 PM - completed front side routing

I did complete the front side routing and get through it it taken a lot of time and I made so many mistakes before at least I finished the routing without any mistakes by far this is the hardest part of the project

3/25/2026 - finally done I completed all the details

I thought this project would to take so much time but with enough head bumping it finally completed and I am very grateful to what have I done thanks for support guys I finally submitted the final components to the GitHub and will be waiting for review

3/27/2026 - successfully ordered the pcb

today successfully ordered the pcb nothing else done today.ordering process is straight forward and simple.why the hell the shipping cost is very high and the cheapest option is 10-13 days

3/29/2026 - ordered mcu

succesfully ordered the mcu rp2040 rp2 b2 in tme for ~2 dollars each that's it delevery charges are insane to india they are very high we can't think about buying anything in this economy