
Scrapped
matarga/simple-devboard
Mk1 is the internal name of this project. I am using this as a way to learn about PCB design and embedded systems and make a "final" out of it.

Mk1 is the internal name of this project. I am using this as a way to learn about PCB design and embedded systems and make a "final" out of it. The "final" that I have made is a simple, low-cost, ESP32-S3 development board. I originally added tons of sensors and complexity but shaved them off to make the project more attainable.
Scrapped is an open-source printed circuit board by matarga, from the matarga/simple-devboard repository on GitHub. It is a 2-layer board of 25 × 40.5 mm with 33 parts on 63 nets, routed with 335 tracks and 22 vias.
It is built around the FT231XQ-R and TLV75533PDRV. Its parts include 14 capacitors, 11 resistors, 3 ICs, 2 transistors and 2 switches. It belongs with the sensors and measurement and microcontroller boards boards and the ESP32 boards of this library.
Mk1 is the internal name of this project. I am using this as a way to learn about PCB design and embedded systems and make a "final" out of it. The "final" that I have made is a simple, low-cost, ESP32-S3 development board. I originally added tons of sensors and complexity but shaved them off to make the project more attainable. The board functions similar to most other boards, boasting a USB to Serial converter, a sample IMU sensor for SPI testing, and extra essentials like auto reset circuits and a voltage regulator. The board has gone well but I advise most to not use any of these designs for future projects of their own. If you do, don't be surprised when it blows up in your face.
Horizons reviews please check in the /REVIEWERS folder
Journal logs are in the /documentation folder of this repo
The schematic breakdown goes as follows:
The power rails start with two decoupling capacitors before then merging with reset and boot circuit through pull up resistors
The IMU is a simple MPU-9250 following the schematic posted its online datasheet

The USB to Serial IC is a FTDI FT231XQ also following the schematic posted in its datasheet

The auto reset circuit is a set of two 2N3984 transistors that feed into the DTR and RTS pins of the FT231XQ, When a handshake is sent by the flashing device the devboard can enter bootloader states without the need of a button press on the board, though the buttons are still included as a fallback

The port is simple with only two 5K1 resistors for USB power negotiation on both sides.

The voltage regulator includes one TLV75533PDRV from TI and decoupling capacitors on power ins and outs. And the reset pin is tied to power to keep the chip on while the board has power.

The PCB is extremely messy.
| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 0.1uF | Capacitor_SMD:C_01005_0402Metric | C3, C4, C9, C10, C14, C20 |
| 4 | 10uF | Capacitor_SMD:C_01005_0402Metric | C13, C15, C16, C18 |
| 4 | 12K | Resistor_SMD:R_0201_0603Metric | R4, R5, R6, R8 |
| 2 | 10K | Resistor_SMD:R_0201_0603Metric | R3, R9 |
| 2 | 1uF | Capacitor_SMD:C_01005_0402Metric | C5, C6 |
| 2 | 2N3904 | Package_TO_SOT_THT:TO-92Flat | Q1, Q2 |
| 2 | 470R | Resistor_SMD:R_0201_0603Metric | R16, R17 |
| 2 | 5K1 | Resistor_SMD:R_0201_0603Metric | R1, R2 |
| 2 | SW_Push | Button_Switch_SMD:SW_SPST_B3U-1000P | SW1, SW2 |
| 1 | 0.1uF | Capacitor_SMD:C_0201_0603Metric | C11 |
| 1 | 22uF | Capacitor_SMD:C_01005_0402Metric | C12 |
| 1 | 4.7K | Resistor_SMD:R_0201_0603Metric | R7 |
| 1 | ESP32-S3-WROOM-2 | RF_Module:ESP32-S3-WROOM-2 | U1 |
| 1 | FT231XQ | Package_DFN_QFN:QFN-20-1EP_4x4mm_P0.5mm_EP2.5x2.5mm | U9 |
| 1 | TLV75533PDRV | Package_SON:WSON-6-1EP_2x2mm_P0.65mm_EP1x1.6mm | U2 |
| 1 | USB_C_Receptacle_USB2.0_14P | Connector_USB:USB_C_Receptacle_G-Switch_GT-USB-7025 | J1 |
It measures 25 × 40.5 mm and has 2 copper layers, 1.6 mm thick.
33 parts, built around the FT231XQ-R and TLV75533PDRV. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
From the matarga/simple-devboard repository on GitHub, at the commit this page was made from: the board is CAD/Kicad/scrapped/rev4/Kicad.kicad_pcb and its schematic CAD/Kicad/Kicad.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Its repository states no licence, so its author keeps all rights: ask matarga before reusing the design.

matarga/simple-devboard
Mk1 is the internal name of this project. I am using this as a way to learn about PCB design and embedded systems and make a "final" out of it.

matarga/simple-devboard
Mk1 is the internal name of this project. I am using this as a way to learn about PCB design and embedded systems and make a "final" out of it.

matarga/simple-devboard
Mk1 is the internal name of this project. I am using this as a way to learn about PCB design and embedded systems and make a "final" out of it.

matarga/simple-devboard
Mk1 is the internal name of this project. I am using this as a way to learn about PCB design and embedded systems and make a "final" out of it.

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