# Biological Apricot P.K.E. Meter ## Description 12V Stepper Motor Driver Board with A4988, ATmega328P, USB-C CH340 Interface, and Onboard 12V→5V Buck Regulation ## Project Details - **Owner:** ahmedalzenk - **Created:** 12/11/2025 - **Last Updated:** 12/11/2025 - **Visibility:** Public - **Power Requirements:** USB - **Software:** Arduino - **Manufacturing Quantity Target:** 10 - **License:** https://www.gnu.org/licenses/gpl-3.0.html - **System Architecture:** ```mermaid flowchart TD J12V["12V Barrel Jack"] --> BKVIN["12V to 5V Buck Converter VIN"] J12V --> A4988_VMOT["A4988 VMOT 12V"] BKVIN --> BK5V["Buck Converter 5V OUT"] BK5V --> MCU_VCC["ATmega328P VCC 5V"] BK5V --> CH340_VCC["CH340 VCC 5V"] USBC["USB-C Receptacle"] --> DPLUS["D+ Line"] USBC --> DMINUS["D- Line"] USBC --> CCCONN["CC Pins"] DPLUS --> CH340_DPLUS["CH340 D+"] DMINUS --> CH340_DMINUS["CH340 D-"] CCCONN --> CH340_CC["CH340 CC/Config"] ``` - **Domain:** Industrial/Manufacturing - **Operating Voltage:** 12V - **Part Type:** Power Management - **Reference Design URL:** https://www.pololu.com/product/1182 - **Connectivity:** USB ## Key Components ### J1 — [PJ-011A](https://www.flux.ai/jecstronic/pj-011a~w4v.md) - Datasheet URL: https://www.cuidevices.com/product/resource/pj-011a.pdf - Manufacturer Name: CUI Devices - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: 12V DC barrel jack power input - Part Type: Connector - Manufacturer Part Number: PJ-011A **Pins:** - ~ [pin 2] - ~ [pin 1] - ~ [pin 3] ### J2 — [2024100002](https://www.flux.ai/adrian95/2024100002~atk.md) - Manufacturer Part Number: 2024100002 - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: USB-C receptacle for CH340 USB-to-serial interface - Part Type: Connector - Datasheet URL: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/834/202410002_Pkg_Spec.pdf - Manufacturer Name: Molex **Pins:** - CC1 [pin A5] - CC2 [pin B5] - DA- [pin A7] - DA+ [pin A6] - DB- [pin B7] - DB+ [pin B6] - GND1 [pin A1] - GND2 [pin A12] - GND3 [pin B1] - GND4 [pin B12] - RX1- [pin B10] - RX1+ [pin B11] - RX2- [pin A10] - RX2+ [pin A11] - SBU1 [pin A8] - SBU2 [pin B8] - SHIELD1 [pin SH1] - SHIELD2 [pin SH2] - SHIELD3 [pin SH3] - SHIELD4 [pin SH4] - TX1- [pin A3] - TX1+ [pin A2] - TX2- [pin B3] - TX2+ [pin B2] - VBUS1 [pin A4] - VBUS2 [pin A9] - VBUS3 [pin B4] - VBUS4 [pin B9] ### U1 — [A4988SETTR-T](https://www.flux.ai/adrian95/a4988settr-t~0cn.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: Switching - Datasheet URL: https://www.allegromicro.com/~/media/Files/Datasheets/A4988-Datasheet.ashx - Manufacturer Name: Allegro MicroSystems - Part Type: Integrated Circuit - Package: 28-QFN - Role Details: Stepper motor driver, full-step configuration - Manufacturer Part Number: A4988SETTR-T **Pins:** - ~ENABLE [pin 2] - ~RESET [pin 12] - ~SLEEP [pin 14] - CP1 [pin 4] - CP2 [pin 5] - DIR [pin 19] - GND1 [pin 3] - GND2 [pin 18] - MS1 [pin 9] - MS2 [pin 10] - MS3 [pin 11] - OUT1A [pin 24] - OUT1B [pin 21] - OUT2A [pin 26] - OUT2B [pin 1] - PAD [pin 29] - REF [pin 17] - ROSC [pin 13] - SENSE1 [pin 23] - SENSE2 [pin 27] - STEP [pin 16] - VBB1 [pin 22] - VBB2 [pin 28] - VCP [pin 6] - VDD [pin 15] - VREG [pin 8] ### U2 — [ATMEGA328P-AN](https://www.flux.ai/adrian95/atmega328p-an~elk.md) - Role Details: 5V 16 MHz microcontroller - Datasheet URL: https://ww1.microchip.com/downloads/en/DeviceDoc/ATmega48A-PA-88A-PA-168A-PA-328-P-DS-DS40002061B.pdf - Manufacturer Name: Microchip Technology - Manufacturer Part Number: ATMEGA328P-AN - Role: Processor - License: https://creativecommons.org/licenses/by/4.0/ - Package: 32-TQFP - Part Type: Microcontroller **Pins:** - (PCINT0/CLKO/ICP1)_PB0 [pin 12] - (PCINT1/OC1A)_PB1 [pin 13] - (PCINT19/OC2B/INT1)_PD3 [pin 1] - (PCINT2/~SS~/OC1B)_PB2 [pin 14] - (PCINT20/XCK/T0)_PD4 [pin 2] - (PCINT21/OC0B/T1)_PD5 [pin 9] - (PCINT22/OC0A/AIN0)_PD6 [pin 10] - (PCINT23/AIN1)_PD7 [pin 11] - (PCINT3/OC2A/MOSI)_PB3 [pin 15] - (PCINT4/MISO)_PB4 [pin 16] - (PCINT6/XTAL1/TOSC1)_PB6 [pin 7] - (PCINT7/XTAL2/TOSC2)_PB7 [pin 8] - ADC6 [pin 19] - ADC7 [pin 22] - AREF [pin 20] - AVCC [pin 18] - GND_1 [pin 3] - GND_2 [pin 5] - GND_3 [pin 21] - PB5_(SCK/PCINT5) [pin 17] - PC0_(ADC0/PCINT8) [pin 23] - PC1_(ADC1/PCINT9) [pin 24] - PC2_(ADC2/PCINT10) [pin 25] - PC3_(ADC3/PCINT11) [pin 26] - PC4_(ADC4/SDA/PCINT12) [pin 27] - PC5_(ADC5/SCL/PCINT13) [pin 28] - PC6_(~RESET~/PCINT14) [pin 29] - PD0_(RXD/PCINT16) [pin 30] - PD1_(TXD/PCINT17) [pin 31] - PD2_(INT0/PCINT18) [pin 32] - VCC_1 [pin 4] - VCC_2 [pin 6] ### U3 — [CH340E](https://www.flux.ai/kicad-part-library/ch340e~64.md) - Datasheet URL: https://www.mpja.com/download/35227cpdata.pdf - Package or Case Code: MSOP-10_3x3mm_P0.5mm - Role Details: USB-to-serial bridge - Role: Interface - Manufacturer Part Number: CH340E - Package: MSOP-10_3x3mm_P0.5mm **Pins:** - ~{CTS} [pin 5] - ~{RTS} [pin 4] - GND [pin 3] - RXD [pin 9] - TNOW [pin 6] - TXD [pin 8] - UD- [pin 2] - UD+ [pin 1] - V3 [pin 10] - VCC [pin 7] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/ahmedalzenk/biological-apricot-ppkpep-meter~rd](https://www.flux.ai/ahmedalzenk/biological-apricot-ppkpep-meter~rd).* --- *Generated from [https://www.flux.ai/ahmedalzenk/biological-apricot-ppkpep-meter~rd](https://www.flux.ai/ahmedalzenk/biological-apricot-ppkpep-meter~rd)*