# Wearable EEG BCI Acquisition Board ## Description Wearable 8-channel EEG/BCI acquisition board with ADS1299, STM32L152, ESP32 Wi-Fi/Bluetooth, LiPo charging, USB-UART, microSD logging, and 4-layer mixed-signal layout constraints. ## Project Details - **Owner:** binyhan - **Created:** 6/27/2026 - **Last Updated:** 6/27/2026 - **Visibility:** Public - **Domain:** Wearable - **Connectivity:** Bluetooth - **Implementation Details:** 8-channel EEG/BCI prototype using ADS1299, STM32L152RET6, ESP32-WROOM-32E, LiPo charging, USB-C, microSD, and 55x40mm 4-layer PCB target. - **Compliance:** FCC - **Power Requirements:** Battery ## Key Components ### D1 — [Generic LED SMD](https://www.flux.ai/jharwinbarrozo/generic-led-smd~ku.md) - Role: Indication - Package: LED_0402_1005Metric - Part Type: LED **Pins:** - A [pin 2] - K [pin 1] ### D2 — [ESD601DPYRQ1](https://www.flux.ai/adrian95/esd601dpyrq1~jxk.md) - Role: Protection - Manufacturer Name: Texas Instruments - Role Details: Low-capacitance electrode input ESD clamp to AGND after 4.7k series resistor - Part Type: Diode - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: ESD601DPYRQ1 - Datasheet URL: https://www.ti.com/lit/ds/symlink/esd601-q1.pdf?ts=1731602930370 **Pins:** - 1 [pin 1] - 2 [pin 2] ### D3 — [ESD601DPYRQ1](https://www.flux.ai/adrian95/esd601dpyrq1~jxk.md) - Datasheet URL: https://www.ti.com/lit/ds/symlink/esd601-q1.pdf?ts=1731602930370 - Manufacturer Part Number: ESD601DPYRQ1 - License: https://creativecommons.org/licenses/by/4.0/ - Role: Protection - Part Type: Diode - Manufacturer Name: Texas Instruments - Role Details: Low-capacitance electrode input ESD clamp to AGND after 4.7k series resistor **Pins:** - 1 [pin 1] - 2 [pin 2] ### D4 — [ESD601DPYRQ1](https://www.flux.ai/adrian95/esd601dpyrq1~jxk.md) - Manufacturer Name: Texas Instruments - Role: Protection - Part Type: Diode - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: ESD601DPYRQ1 - Datasheet URL: https://www.ti.com/lit/ds/symlink/esd601-q1.pdf?ts=1731602930370 - Role Details: Low-capacitance electrode input ESD clamp to AGND after 4.7k series resistor **Pins:** - 1 [pin 1] - 2 [pin 2] ### D5 — [ESD601DPYRQ1](https://www.flux.ai/adrian95/esd601dpyrq1~jxk.md) - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: ESD601DPYRQ1 - Role Details: Low-capacitance electrode input ESD clamp to AGND after 4.7k series resistor - Datasheet URL: https://www.ti.com/lit/ds/symlink/esd601-q1.pdf?ts=1731602930370 - Manufacturer Name: Texas Instruments - Role: Protection - Part Type: Diode **Pins:** - 1 [pin 1] - 2 [pin 2] ### D6 — [ESD601DPYRQ1](https://www.flux.ai/adrian95/esd601dpyrq1~jxk.md) - Part Type: Diode - Manufacturer Name: Texas Instruments - Role: Protection - Manufacturer Part Number: ESD601DPYRQ1 - Datasheet URL: https://www.ti.com/lit/ds/symlink/esd601-q1.pdf?ts=1731602930370 - Role Details: Low-capacitance electrode input ESD clamp to AGND after 4.7k series resistor - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - 1 [pin 1] - 2 [pin 2] ### D7 — [ESD601DPYRQ1](https://www.flux.ai/adrian95/esd601dpyrq1~jxk.md) - Manufacturer Name: Texas Instruments - Part Type: Diode - License: https://creativecommons.org/licenses/by/4.0/ - Role: Protection - Role Details: Low-capacitance electrode input ESD clamp to AGND after 4.7k series resistor - Manufacturer Part Number: ESD601DPYRQ1 - Datasheet URL: https://www.ti.com/lit/ds/symlink/esd601-q1.pdf?ts=1731602930370 **Pins:** - 1 [pin 1] - 2 [pin 2] ### D8 — [ESD601DPYRQ1](https://www.flux.ai/adrian95/esd601dpyrq1~jxk.md) - Datasheet URL: https://www.ti.com/lit/ds/symlink/esd601-q1.pdf?ts=1731602930370 - Manufacturer Part Number: ESD601DPYRQ1 - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Low-capacitance electrode input ESD clamp to AGND after 4.7k series resistor - Part Type: Diode - Manufacturer Name: Texas Instruments - Role: Protection **Pins:** - 1 [pin 1] - 2 [pin 2] ### D9 — [ESD601DPYRQ1](https://www.flux.ai/adrian95/esd601dpyrq1~jxk.md) - Datasheet URL: https://www.ti.com/lit/ds/symlink/esd601-q1.pdf?ts=1731602930370 - Manufacturer Part Number: ESD601DPYRQ1 - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Low-capacitance electrode input ESD clamp to AGND after 4.7k series resistor - Part Type: Diode - Manufacturer Name: Texas Instruments - Role: Protection **Pins:** - 1 [pin 1] - 2 [pin 2] ### J1 — [TSW-103-07-G-D](https://www.flux.ai/adrian95/tsw-103-07-g-d~6gs.md) - Manufacturer Name: Samtec Inc. - Part Type: Connector - Role: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://suddendocs.samtec.com/prints/tsw-xxx-xx-x-x-xx-xxx-footprint.pdf - Role Details: 2x3 SWD header: 3V3, SWDIO, GND, SWCLK, NRST, GND - Manufacturer Part Number: TSW-103-07-G-D **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] ### J2 — [USB4215-03-A](https://www.flux.ai/adrian95/usb4215-03-a~kg3.md) - Package or Case Code: GCT_USB4215-03-A_REVA - Part Type: USB C - Datasheet URL: https://gct.co/files/specs/usb4215-spec.pdf - Symbol Style: parametric-v1 - Manufacturer Name: GCT - Manufacturer Part Number: USB4215-03-A - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: USB-C receptacle: VBUS to charger and CP2102N, CC1/CC2 each 5.1k to GND, D+/D- to CP2102N - Role: Connector **Pins:** - CC1 [pin A5] - CC2 [pin B5] - DN1 [pin A7] - DN2 [pin B7] - DP1 [pin A6] - DP2 [pin B6] - GND_A [pin A1_B12] - GND_B [pin B1_A12] - SBU1 [pin A8] - SBU2 [pin B8] - SHIELD [pin SH1] - SHIELD [pin SH4] - SHIELD [pin SH2] - SHIELD [pin SH3] - VBUS_A [pin A4_B9] - VBUS_B [pin B4_A9] ### J3 — [53398-1271](https://www.flux.ai/cherepanyadima/53398-1271.md) - Manufacturer Part Number: 53398-1271 - Manufacturer Name: Molex - Role Details: 12-pin electrode connector: CH1-CH8, BIAS, REF, AGND shield, spare - Part Type: Connectors - Role: Connector - Datasheet URL: http://www.molex.com/pdm_docs/sd/533981271_sd.pdf - Mount: Surface Mount **Pins:** - 1 [pin 1] - 10 [pin 10] - 11 [pin 11] - 12 [pin 12] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] - 7 [pin 7] - 8 [pin 8] - 9 [pin 9] ### J4 — [DM3AT-SF-PEJM5](https://www.flux.ai/adrian95/dm3at-sf-pejm5~p1p.md) - Manufacturer Part Number: DM3AT-SF-PEJM5 - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Manufacturer Name: Hirose Electric Co Ltd - Datasheet URL: https://www.mouser.com/datasheet/2/185/DM3AT_SF_PEJM5_CL0609_0031_0_00_2DDrawing_00009471-1614303.pdf - Role: Connector - Role Details: microSD socket on ESP32 VSPI: IO14 CLK, IO12 DAT0/MISO with boot pulldown, IO13 CMD/MOSI, IO15 DAT3/CS with pullup; separate from STM32-ESP SPI2 **Pins:** - ~ [pin SWA] - ~ [pin SWB] - CD/DAT3 [pin 2] - CLK [pin 5] - CMD [pin 3] - DAT0 [pin 7] - DAT1 [pin 8] - DAT2 [pin 1] - SHIELD [pin P3] - SHIELD [pin P4] - SHIELD [pin P1] - SHIELD [pin P2] - VDD [pin 4] - VSS [pin 6] ### J5 — [S2B-PH-SM4-TB(LF)(SN)](https://www.flux.ai/adrian95/s2b-ph-sm4-tblfsn~b96.md) - Manufacturer Part Number: S2B-PH-SM4-TB(LF)(SN) - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: JST Sales America Inc. - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf - Role: Connector - Role Details: JST-PH 2.0mm 2-pin LiPo battery connector, +VBAT and GND, 500-1000mAh battery target **Pins:** - P1 [pin 1] - P2 [pin 2] ### Q1 — [MMBT3904 RFG](https://www.flux.ai/lcsc/mmbt3904-rfg~6908.md) - Role: Switching - Product Info Url: https://lcsc.com/product-detail/New-Arrivals_Taiwan-Semiconductor-Taiwan-Semicon-MMBT3904-RFG_C483927.html - Role Details: NPN transistor in CP2102N DTR/RTS auto-reset circuit driving ESP32 EN - Manufacturer Part Number: MMBT3904 RFG - Part Type: Bipolar Transistors - BJT - Package or Case Code: SOT-23-3_L2.9-W1.3-P1.90-LS2.4-BR - LCSC Part Number: C483927 - Manufacturer Name: Taiwan Semiconductor(台湾半导体) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2001151033_Taiwan-Semiconductor-MMBT3904-RFG_C483927.pdf - JLCPCB Part Class: Extended Part **Pins:** - B [pin 1] - C [pin 3] - E [pin 2] ### Q2 — [MMBT3904 RFG](https://www.flux.ai/lcsc/mmbt3904-rfg~6908.md) - JLCPCB Part Class: Extended Part - Role: Switching - Role Details: NPN transistor in CP2102N DTR/RTS auto-boot circuit driving ESP32 IO0 - Manufacturer Name: Taiwan Semiconductor(台湾半导体) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2001151033_Taiwan-Semiconductor-MMBT3904-RFG_C483927.pdf - LCSC Part Number: C483927 - Package or Case Code: SOT-23-3_L2.9-W1.3-P1.90-LS2.4-BR - Part Type: Bipolar Transistors - BJT - Manufacturer Part Number: MMBT3904 RFG - Product Info Url: https://lcsc.com/product-detail/New-Arrivals_Taiwan-Semiconductor-Taiwan-Semicon-MMBT3904-RFG_C483927.html **Pins:** - B [pin 1] - C [pin 3] - E [pin 2] ### SW1 — [PTS636 SM25J SMTR LFS](https://www.flux.ai/jecstronic/pts636-sm25j-smtr-lfs~plx.md) - Datasheet URL: https://www.ckswitches.com/media/2779/pts636.pdf - Role: Switching - Manufacturer Part Number: PTS636 SM25J SMTR LFS - Manufacturer Name: C&K - Part Type: Switch - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Reset button from ESP32 EN to GND **Pins:** - ~ [pin 1B] - ~ [pin 1A] ### SW2 — [PTS636 SM25J SMTR LFS](https://www.flux.ai/jecstronic/pts636-sm25j-smtr-lfs~plx.md) - Manufacturer Name: C&K - Role Details: Boot button from ESP32 IO0 to GND - Manufacturer Part Number: PTS636 SM25J SMTR LFS - Datasheet URL: https://www.ckswitches.com/media/2779/pts636.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Role: Switching - Part Type: Switch **Pins:** - ~ [pin 1B] - ~ [pin 1A] ### SW4 — [DPDT_5A_SlideSwitch](https://www.flux.ai/tpetrovic2/dpdt5aslideswitch~rs.md) - Part Type: Switch - Role Details: 5 A SMD DPDT slide switch used as main LiPo power switch; one pole connects +VBAT to +VSYS, unused pole pins marked no-connect - Datasheet URL: https://sten-eswitch-13110800-production.s3.amazonaws.com/system/asset/product_line/data_sheet/115/500.pdf - Role: Switch - Manufacturer Part Number: 500SDP1S1M2QEA - Manufacturer Name: E-Switch **Pins:** - P1 [pin 1] - P2 [pin 2] - P3 [pin 3] - P4 [pin 4] - P5 [pin 5] - P6 [pin 6] ### U1 — [ADS1299IPAGR](https://www.flux.ai/adrian95/ads1299ipagr~gsz.md) - Part Type: Integrated Circuit - Role Details: ADS1299 EEG AFE; AVDD +5V0A, AVSS AGND, DVDD/IOVDD +3V3, DGND GND; internal oscillator via CLKSEL high - Role: Sensing (Shunt) - Datasheet URL: https://www.ti.com/lit/ds/symlink/ads1299.pdf - Manufacturer Name: Texas Instruments - Manufacturer Part Number: ADS1299IPAGR - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - ~CS [pin 39] - ~DRDY [pin 47] - ~PWDN [pin 35] - ~RESET [pin 36] - AVDD_1 [pin 19] - AVDD_2 [pin 22] - AVDD_3 [pin 23] - AVDD_4 [pin 56] - AVDD_5 [pin 59] - AVDD1 [pin 54] - AVSS_1 [pin 20] - AVSS_2 [pin 21] - AVSS_3 [pin 32] - AVSS_4 [pin 57] - AVSS_5 [pin 58] - AVSS1 [pin 53] - BIASIN [pin 62] - BIASINV [pin 61] - BIASOUT [pin 63] - BIASREF [pin 60] - CLK [pin 37] - CLKSEL [pin 52] - DAISY_IN [pin 41] - DGND_1 [pin 33] - DGND_2 [pin 49] - DGND_3 [pin 51] - DIN [pin 34] - DOUT [pin 43] - DVDD_1 [pin 48] - DVDD_2 [pin 50] - GPIO1 [pin 42] - GPIO2 [pin 44] - GPIO3 [pin 45] - GPIO4 [pin 46] - IN1N [pin 15] - IN1P [pin 16] - IN2N [pin 13] - IN2P [pin 14] - IN3N [pin 11] - IN3P [pin 12] - IN4N [pin 9] - IN4P [pin 10] - IN5N [pin 7] - IN5P [pin 8] - IN6N [pin 5] - IN6P [pin 6] - IN7N [pin 3] - IN7P [pin 4] - IN8N [pin 1] - IN8P [pin 2] - NC_1 [pin 27] - NC_2 [pin 29] - RESERVED [pin 64] - RESV1 [pin 31] - SCLK [pin 40] - SRB1 [pin 17] - SRB2 [pin 18] - START [pin 38] - VCAP1 [pin 28] - VCAP2 [pin 30] - VCAP3 [pin 55] - VCAP4 [pin 26] - VREFN [pin 25] - VREFP [pin 24] ### U2 — [STM32L152RET6](https://www.flux.ai/lcsc/stm32l152ret6~oaap.md) - Manufacturer Name: ST(意法半导体) - JLCPCB Part Class: Extended Part - LCSC Part Number: C1337532 - Role: Logic-level Shifting - Role Details: STM32L152RET6 MCU; SPI1 master to ADS1299; SWD debug header; +3V3 supply - Manufacturer Part Number: STM32L152RET6 - Package or Case Code: LQFP-64_L10.0-W10.0-P0.50-LS12.0-BL **Pins:** - BOOT0 [pin 60] - NRST [pin 7] - PA0-WKUP1 [pin 14] - PA1 [pin 15] - PA10 [pin 43] - PA11 [pin 44] - PA12 [pin 45] - PA13 [pin 46] - PA14 [pin 49] - PA15 [pin 50] - PA2 [pin 16] - PA3 [pin 17] - PA4 [pin 20] - PA5 [pin 21] - PA6 [pin 22] - PA7 [pin 23] - PA8 [pin 41] - PA9 [pin 42] - PB0 [pin 26] - PB1 [pin 27] - PB10 [pin 29] - PB11 [pin 30] - PB12 [pin 33] - PB13 [pin 34] - PB14 [pin 35] - PB15 [pin 36] - PB2 [pin 28] - PB3 [pin 55] - PB4 [pin 56] - PB5 [pin 57] - PB6 [pin 58] - PB7 [pin 59] - PB8 [pin 61] - PB9 [pin 62] - PC0 [pin 8] - PC1 [pin 9] - PC10 [pin 51] - PC11 [pin 52] - PC12 [pin 53] - PC13-WKUP2 [pin 2] - PC14-OSC32_IN [pin 3] - PC15-OSC32_OUT [pin 4] - PC2 [pin 10] - PC3 [pin 11] - PC4 [pin 24] - PC5 [pin 25] - PC6 [pin 37] - PC7 [pin 38] - PC8 [pin 39] - PC9 [pin 40] - PD2 [pin 54] - PH0-OSC_IN [pin 5] - PH1-OSC_OUT [pin 6] - VDD_1 [pin 32] - VDD_2 [pin 48] - VDD_3 [pin 64] - VDD_4 [pin 19] - VDDA [pin 13] - VLCD [pin 1] - VSS_1 [pin 31] - VSS_2 [pin 47] - VSS_3 [pin 63] - VSS_4 [pin 18] - VSSA [pin 12] ### U3 — [ESP32-WROOM-32E](https://www.flux.ai/vasyl/esp32-wroom-32e~epi.md) - Datasheet URL: https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32_datasheet_en.pdf - Part Type: Integrated Circuit - Capacitor 2: 10 µF, 16 V, 1206 package (Ceramic) - Role: Modulation / Demodulation - Role Details: ESP32-WROOM-32E radio module; SPI2 link to STM32; +3V3 power with WiFi TX bulk capacitance; EN/IO0 boot controls - License: https://creativecommons.org/licenses/by/4.0/ - Resistor: 10 kΩ, 1206 package (Chip SMD) - Symbol Style: parametric-v1 - Manufacturer Part Number: ESP32-WROOM-32 - Manufacturer Name: Espressif Systems - Capacitor 1: 100 nF, 25 V, 1206 package x2 (Ceramic) **Pins:** - EN [pin 3] - GND [pin 38] - GND [pin 39] - GND [pin 15] - GND [pin 1] - IO0 [pin 25] - IO12 [pin 14] - IO13 [pin 16] - IO14 [pin 13] - IO15 [pin 23] - IO16 [pin 27] - IO17 [pin 28] - IO18 [pin 30] - IO19 [pin 31] - IO2 [pin 24] - IO21 [pin 33] - IO22 [pin 36] - IO23 [pin 37] - IO25 [pin 10] - IO26 [pin 11] - IO27 [pin 12] - IO32 [pin 8] - IO33 [pin 9] - IO34 [pin 6] - IO35 [pin 7] - IO4 [pin 26] - IO5 [pin 29] - NC [pin 32] - RXD0/IO3 [pin 34] - SCK/CLK [pin 20] - SCS/CMD [pin 19] - SDI/SD1 [pin 22] - SDO/SD0 [pin 21] - SENSOR_VN [pin 5] - SENSOR_VP [pin 4] - SHD/SD2 [pin 17] - SWP/SD3 [pin 18] - TXD0/IO1 [pin 35] - VDD [pin 2] ### U4 — [MCP73831T-2DCI/OT](https://www.flux.ai/adrian95/mcp73831t-2dciot~0el.md) - Datasheet URL: https://ww1.microchip.com/downloads/aemDocuments/documents/APID/ProductDocuments/DataSheets/MCP73831-Family-Data-Sheet-DS20001984H.pdf - Manufacturer Name: Microchip Technology - License: https://creativecommons.org/licenses/by/4.0/ - Role: Power Conversion - Role Details: VBUS input, +VBAT output, 2k PROG resistor for ~500mA charge current, STAT LED - Manufacturer Part Number: MCP73831T-2DCI/OT - Part Type: Power Management **Pins:** - BAT [pin 3] - CHRG [pin 1] - GND [pin 2] - PROG [pin 5] - VCC [pin 4] ### U5 — [TPS62840DLCR](https://www.flux.ai/lcsc/tps62840dlcr~fpxf.md) - LCSC Part Number: C2071859 - Package or Case Code: VSON-8_L2.0-W1.5-P0.50-BL - Symbol Style: parametric-v1 - JLCPCB Part Class: Extended Part - Role Details: +VSYS input to +3V3 output; use 2.2uH inductor, 10uF input cap, 22uF output cap - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: DC-DC Converters - Manufacturer Name: TI(德州仪器) - Manufacturer Part Number: TPS62840DLCR - Datasheet URL: https://www.lcsc.com/datasheet/C2071859.pdf?spm=wm.sxq.inf.ggs&lcsc_vid=FlkNBAIDRQULVABfFAVZBgZVFVZYBgZSQ1NeBVIFQlExVlNRTlhaX1NSQlVfVzsOAxUeFF5JWBYZEEoKFBINSQcJGk4dAgUUFAk%3D - Role: Power Conversion **Pins:** - EN [pin 4] - GND [pin 1] - MODE [pin 3] - STOP [pin 6] - SW [pin 7] - VIN [pin 2] - VOS [pin 8] - VSET [pin 5] ### U6 — [TPS61023DRLR](https://www.flux.ai/lcsc/tps61023drlr~qygu.md) - Operating Temperature: -40℃~+125℃@(TJ) - License: https://creativecommons.org/licenses/by/4.0/ - Output Current: 3A - Role: Power Conversion - LCSC Part Number: C919459 - Datasheet URL: https://www.ti.com/lit/ds/symlink/tps61023.pdf?HQS=dis-dk-null-digikeymode-dsf-pf-null-wwe&ts=1780366470639&ref_url=https%253A%252F%252Fwww.icbanq.com%252F - Max Input Voltage: 500mV~5.5V - Manufacturer Name: TI(德州仪器) - Logic Function: Boost type - Max Output Voltage: 2.2~5.5V - Symbol Style: parametric-v1 - Frequency: 1MHz - Manufacturer Part Number: TPS61023DRLR - Role Details: +VSYS input to +5V5 output; use 1uH inductor and feedback divider for 5.5V - JLCPCB Part Class: Extended Part - Package or Case Code: SOT-563_L1.6-W1.2-P0.50-LS1.6-BR - Part Type: DC-DC Converters **Pins:** - EN [pin 2] - FB [pin 1] - GND [pin 4] - SW [pin 5] - VIN [pin 3] - VOUT [pin 6] ### U7 — [TPS7A2050PDBVR](https://www.flux.ai/lcsc/tps7a2050pdbvr~xwcd.md) - Manufacturer Name: TI(德州仪器) - Part Type: Linear Voltage Regulators (LDO) - LCSC Part Number: C2864504 - Role Details: +5V5 input to +5V0A output; EN tied to +5V5; 1uF input capacitor to AGND; 10uF low-ESR ceramic + 1uF + 100nF output capacitors to AGND close to OUT; pin 4 NC unused - Role: Power Conversion - JLCPCB Part Class: Extended Part - Package or Case Code: SOT-23-5_L2.9-W1.6-P0.95-LS2.8-BR - Manufacturer Part Number: TPS7A2050PDBVR **Pins:** - EN [pin 3] - GND [pin 2] - IN [pin 1] - NC [pin 4] - OUT [pin 5] ### U8 — [CP2102N-A02-GQFN28R](https://www.flux.ai/lcsc/cp2102n-a02-gqfn28r~sj5u.md) - Symbol Style: parametric-v1 - Package or Case Code: QFN-28_L5.0-W5.0-P0.50-TL-EP3.3 - Part Type: USB ICs - JLCPCB Part Class: Extended Part - Operating Temperature: -40℃~+85℃@(Ta) - Supply Voltage: 3~3.6V - LCSC Part Number: C964632 - Role: Logic-level Shifting - Logic Function: USB to UART - Manufacturer Part Number: CP2102N-A02-GQFN28R - Datasheet URL: https://www.lcsc.com/datasheet/C964632.pdf?spm=wm.sxq.inf.ggs&lcsc_vid=FlkNBAIDRQULVABfFAVZBgZVFVZYBgZSQ1NeBVIFQlExVlNeR1VeU1dTRVhaUTsOAxUeFF5JWBYZEEoKFBINSQcJGk4dAgUUFAk%3D - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: SKYWORKS/SILICON LABS(芯科) - Role Details: CP2102N USB-UART powered by +3V3; USB D+/D- to USB-C, TXD to ESP IO3, RXD to ESP IO1, DTR/RTS to ESP32 auto-reset/boot transistors **Pins:** - CHR0 [pin 15] - CHR1 [pin 14] - CHREN [pin 13] - CTS [pin 23] - D- [pin 5] - D+ [pin 4] - DCD [pin 1] - DSR [pin 27] - DTR [pin 28] - EP [pin 29] - GND [pin 3] - GPIO.0/TXT [pin 19] - GPIO.1/RXT [pin 18] - GPIO.2/RS485 [pin 17] - GPIO.3/WAKEUP [pin 16] - GPIO.4 [pin 22] - GPIO.5 [pin 21] - GPIO.6 [pin 20] - NC [pin 10] - RI/CLK [pin 2] - RSTb [pin 9] - RTS [pin 24] - RXD [pin 25] - SUSPEND [pin 12] - SUSPENDb [pin 11] - TXD [pin 26] - VBUS [pin 8] - VDD [pin 6] - VREGIN [pin 7] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/binyhan/wearable-eeg-bci-acquisition-board~dk](https://www.flux.ai/binyhan/wearable-eeg-bci-acquisition-board~dk).* --- *Generated from [https://www.flux.ai/binyhan/wearable-eeg-bci-acquisition-board~dk](https://www.flux.ai/binyhan/wearable-eeg-bci-acquisition-board~dk)*