# ATmega328P USB-Serial Breakout ## Description Arduino Nano-style ATmega328P breakout with CH340G USB-to-serial interface, USB power input, reset/clock support, and programming headers. ## Project Details - **Owner:** aj543 - **Created:** 6/17/2026 - **Last Updated:** 6/17/2026 - **Visibility:** Public ## Key Components ### J1 — [MicroXNJ](https://www.flux.ai/lcsc/microxnj~e8u3.md) - Connector Rows: N/A - Package or Case Code: MICRO-USB-SMD_MICROXNJ - Part Type: USB Connectors - Connector Type: USB Connectors - Connector Gender: Female - Manufacturer Part Number: MicroXNJ - JLCPCB Part Class: Extended Part - Manufacturer Name: SHOU HAN(首韩) - Role: USB Connector - Product Info Url: https://lcsc.com/product-detail/USB-Connectors_SHOU-HAN-MicroXNJ_C404969.html - Connector Pitch: 0.8mm - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2204151400_SHOU-HAN-MicroXNJ_C404969.pdf - Connector Positions: N/A - LCSC Part Number: C404969 **Pins:** - D- [pin 2] - D+ [pin 3] - GND [pin 5] - ID [pin 4] - SH1 [pin 6] - SH2 [pin 7] - SH3 [pin 8] - SH4 [pin 9] - VBUS [pin 1] ### J2 — [X5521FV-2x15-C85D30-1150](https://www.flux.ai/lcsc/x5521fv-2x15-c85d30-1150~iuge.md) - Symbol Style: parametric-v1 - Manufacturer Name: XKB Connectivity(中国星坤) - Manufacturer Part Number: X5521FV-2x15-C85D30-1150 - Datasheet URL: https://www.lcsc.com/datasheet/C2916939.pdf?spm=wm.sxq.inf.ggs&lcsc_vid=FlVZVVIFFgBeVAVTT1BXUgFfEwJeVlBfEwVcAlMHRAQxVlNRTlhfVlZVRFVWXjsOAxUeFF5JWBYZEEoKFBINSQcJGk4dAgUUFAk%3D - Part Type: Female Headers - Role: I/O Header - JLCPCB Part Class: Extended Part - Package or Case Code: HDR-TH_30P-P2.54-V-F-R2-C15-S2.54-3 - LCSC Part Number: C2916939 **Pins:** - 1 [pin 1] - 10 [pin 10] - 11 [pin 11] - 12 [pin 12] - 13 [pin 13] - 14 [pin 14] - 15 [pin 15] - 16 [pin 16] - 17 [pin 17] - 18 [pin 18] - 19 [pin 19] - 2 [pin 2] - 20 [pin 20] - 21 [pin 21] - 22 [pin 22] - 23 [pin 23] - 24 [pin 24] - 25 [pin 25] - 26 [pin 26] - 27 [pin 27] - 28 [pin 28] - 29 [pin 29] - 3 [pin 3] - 30 [pin 30] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] - 7 [pin 7] - 8 [pin 8] - 9 [pin 9] ### SW1 — [TS-1088-AR02016](https://www.flux.ai/lcsc/ts-1088-ar02016~e3n1.md) - Role: Reset Button - Package or Case Code: SW-SMD_L3.9-W3.0-P4.45 - Manufacturer Name: XUNPU(讯普) - JLCPCB Part Class: Extended Part - Manufacturer Part Number: TS-1088-AR02016 - Product Info Url: https://lcsc.com/product-detail/Tactile-Switches_XUNPU-TS-1088-AR02016_C720477.html - Part Type: Tactile Switches - LCSC Part Number: C720477 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302330_XUNPU-TS-1088-AR02016_C720477.pdf **Pins:** - 1 [pin 1] - 2 [pin 2] ### U1 — [ATMEGA328P-PN](https://www.flux.ai/lcsc/atmega328p-pn~vp28.md) - JLCPCB Part Class: Extended Part - Manufacturer Part Number: ATMEGA328P-PN - LCSC Part Number: C1337455 - Manufacturer Name: MICROCHIP(美国微芯) - Operating Voltage: 5V - Package or Case Code: PDIP-28_L35.0-W7.3-P2.54-LS7.8-BL - Role: MCU **Pins:** - (PCINT0/CLKO/ICP1)PB0 [pin 14] - (PCINT14/RESET#)PC6 [pin 1] - (PCINT16/RXD)PD0 [pin 2] - (PCINT17/TXD)PD1 [pin 3] - (PCINT18/INT0)PD2 [pin 4] - (PCINT19/OC2B/INT1)PD3 [pin 5] - (PCINT20/XCK/T0)PD4 [pin 6] - (PCINT21/OC0B/T1)PD5 [pin 11] - (PCINT22/OC0A/AIN0)PD6 [pin 12] - (PCINT23/AIN1)PD7 [pin 13] - (PCINT6/XTAL1/TOSC1)PB6 [pin 9] - (PCINT7/XTAL2/TOSC2)PB7 [pin 10] - ~{PB2(SS}/OC1B/PCINT2) [pin 16] - AREF [pin 21] - AVCC [pin 20] - GND [pin 8] - GND [pin 22] - PB1(OC1A/PCINT1) [pin 15] - PB3(MOSI/OC2A/PCINT3) [pin 17] - PB4(MISO/PCINT4) [pin 18] - PB5(SCK/PCINT5) [pin 19] - 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] - VCC [pin 7] ### U3 — [CH340K](https://www.flux.ai/lcsc/ch340k~fevo.md) - Manufacturer Part Number: CH340K - Role Details: CH340K used because exact CH340G library part was unavailable; internal clock avoids external CH340G crystal circuit. - Package or Case Code: ESOP-10_L4.9-W3.9-P1.00-LS6.2-BL-EP - JLCPCB Part Class: Extended Part - Operating Temperature: -20℃~+70℃ - Part Type: USB ICs - Manufacturer Name: WCH(南京沁恒) - LCSC Part Number: C968586 - Product Info Url: https://lcsc.com/product-detail/USB-ICs_WCH-Jiangsu-Qin-Heng-CH340K_C968586.html - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2403131131_WCH-Jiangsu-Qin-Heng-CH340K_C968586.pdf - Voltage Supply: 3.3V , 5V **Pins:** - ~{CTS} [pin 5] - ~{DTR} [pin 4] - ~{RTS} [pin 6] - EP [pin 11] - GND [pin 3] - RXD [pin 9] - TXD [pin 8] - UD- [pin 2] - UD+ [pin 1] - V3 [pin 10] - VCC [pin 7] ### Y1 — [ECS-240-20-33-TR](https://www.flux.ai/lcsc/ecs-240-20-33-tr~cbqd.md) - Package or Case Code: CRYSTAL-SMD_4P-L3.2-W2.5-BL - Manufacturer Name: ECS - JLCPCB Part Class: Extended Part - Frequency: 16MHz - Role: Timing - Part Type: Crystals - LCSC Part Number: C441721 - Manufacturer Part Number: ECS-240-20-33-TR **Pins:** - 1 [pin 1] - 3 [pin 3] - GND [pin 2] - GND [pin 4] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/aj543/atmega328p-usb-serial-breakout~u7](https://www.flux.ai/aj543/atmega328p-usb-serial-breakout~u7).* --- *Generated from [https://www.flux.ai/aj543/atmega328p-usb-serial-breakout~u7](https://www.flux.ai/aj543/atmega328p-usb-serial-breakout~u7)*