# Voluntary Lavender T-800 ## Description Low-Power MCU-Based SPI TFT Display Board with Advanced Power Management and Protection ## Project Details - **Owner:** simon26 - **Created:** 11/25/2025 - **Last Updated:** 11/25/2025 - **Visibility:** Public - **Pause reason:** User review requested for board size and mounting approach. - **Human Interface:** Display - **minX:** -43mm - **Power Requirements:** Battery - **Domain:** Consumer Electronics - **maxY:** 25mm - **Power Requirements:** USB - **System Architecture:** flowchart TB MCU[MCU] TFT[SPI TFT + Capacitive Touch] USBC[USB-C UFP] BATT[Li-ion Battery Connector] CHG[Charger IC with Power-Path Management] REG[3.3 V Regulator] BL[Backlight Control] RST[Reset/Programming Header] IO[User I/O] USBC --> CHG BATT --> CHG CHG --> REG REG --> MCU REG --> TFT REG --> BL MCU --> TFT MCU --> IO MCU --> RST - **Human Interface:** Touchscreen - **Operating Voltage:** 3.3V - **Connectivity:** USB - **maxX:** 43mm - **Next step:** Await user feedback or approval on PCB outline sizing and mounting scheme before proceeding with placement and mounting hole definition. - **minY:** -25mm - **Stars:** 1 ## Key Components ### D1 — [Schottky Diode](https://www.flux.ai/corynrobinson/schottky-diode.md) - Manufacturer Part Number: MBR0520LT1G - Package or Case Code: D_SOD-123 - Datasheet URL: https://www.onsemi.com/pdf/datasheet/mbr0520lt1-d.pdf - Role Details: Protect battery input from reverse connection - Current: 0.5A - Role: Reverse Polarity Protection - Manufacturer Name: onsemi - Part Type: Diode - Breakdown Voltage: 20V - Purchase Url: https://octopart.com/mbr0520lt1g-onsemi-2933?r=sp **Pins:** - A - K ### D2 — [6V Unidirectional TVS Diode](https://www.flux.ai/corynrobinson/6v-unidirectional-tvs-diode.md) - Datasheet URL: https://www.littelfuse.com/~/media/electronics/datasheets/tvs_diodes/littelfuse_tvs_diode_smaj_datasheet.pdf.pdf - Package or Case Code: D_SMA - Breakdown Voltage: 6V - Role Details: Clamp transients on USB-C 5 V input - Part Type: Diode - Manufacturer Part Number: SMAJ6.0A - Manufacturer Name: Littlefuse - Role: Overvoltage Protection **Pins:** - A - K ### J1 — [124018312112A](https://www.flux.ai/adrian95/124018312112a.md) - Part Type: Connector - Manufacturer Name: Amphenol ICC (Commercial Products) - Role Details: USB-C upstream-facing connector for power and data - Role: Connector - Datasheet URL: https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/datasheet/inputoutput/io_waterproof_usb_type_c.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 124018312112A **Pins:** - CC1 [pin A5] - CC2 [pin B5] - D1- [pin A7] - D1+ [pin A6] - D2- [pin B7] - D2+ [pin B6] - GND_A [pin A1] - GND_A [pin A12] - GND_B [pin B1] - GND_B [pin B12] - RX1- [pin B10] - RX1+ [pin B11] - RX2- [pin A10] - RX2+ [pin A11] - SBU1 [pin A8] - SBU2 [pin B8] - SHIELD [pin SH2] - SHIELD [pin SH4] - SHIELD [pin SH1] - SHIELD [pin SH3] - TX1- [pin A3] - TX1+ [pin A2] - TX2- [pin B3] - TX2+ [pin B2] - VBUS_A [pin A4] - VBUS_A [pin A9] - VBUS_B [pin B4] - VBUS_B [pin B9] ### J2 — [B2B-PH-K-S(LF)(SN)](https://www.flux.ai/lcsc/b2b-ph-k-slfsn.md) - LCSC Part Number: C131337 - Role: Connector - Connector Positions: 2 - Manufacturer Name: JST - Part Type: Wire To Board / Wire To Wire Connector - JLCPCB Part Class: Extended Part - Connector Gender: Male - Manufacturer Part Number: B2B-PH-K-S(LF)(SN) - Product Info Url: https://lcsc.com/product-detail/PH-Connectors_JST_B2B-PH-K-S-LF-SN_B2B-PH-K-S-LF-SN_C131337.html - Connector Type: Wire To Board Connector - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_JST-B2B-PH-K-S-LF-SN_C131337.pdf - Role Details: Li-ion battery connector - Connector Pitch: 2mm - Connector Rows: 1 - Package or Case Code: CONN-TH_B2B-PH-K-S **Pins:** - 1 [pin 1] - 2 [pin 2] ### J3 — [ARM JTAG SWD 10Pin 0.1" Connector](https://www.flux.ai/vasy_skral/arm-jtag-swd-10pin-01-connector.md) - Part Type: Connector - Role Details: SWD programming and reset header (2×5 2.54 mm) - Role: Programming Interface **Pins:** - ~RESET~ [pin 10] - GND [pin 5] - GND [pin 3] - GNDDetect [pin 9] - NC [pin 7] - NC/TDI [pin 8] - SWDCLK/TCK [pin 4] - SWDIO/TMS [pin 2] - SWO/TDO [pin 6] - VTref [pin 1] ### J4 — [Pin Header 01x06 2.54mm Vertical](https://www.flux.ai/vasy_skral/pin-header-01x06-254mm-vertical.md) - Role Details: 6-pin user I/O header - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Role: User I/O **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] - Pin_4 [pin 4] - Pin_5 [pin 5] - Pin_6 [pin 6] ### U1 — [STM32L072CZT6TR](https://www.flux.ai/lcsc/stm32l072czt6tr.md) - JLCPCB Part Class: Extended Part - Manufacturer Part Number: STM32L072CZT6TR - LCSC Part Number: C1852754 - Role Details: Low-power microcontroller for the system - Package or Case Code: LQFP-48_L7.0-W7.0-P0.50-LS9.0-BL - Role: Main MCU - Manufacturer Name: ST(意法半导体) **Pins:** - BOOT0 [pin 44] - NRST [pin 7] - PA0 [pin 10] - PA1 [pin 11] - PA10 [pin 31] - PA11 [pin 32] - PA12 [pin 33] - PA13 [pin 34] - PA14 [pin 37] - PA15 [pin 38] - PA2 [pin 12] - PA3 [pin 13] - PA4 [pin 14] - PA5 [pin 15] - PA6 [pin 16] - PA7 [pin 17] - PA8 [pin 29] - PA9 [pin 30] - PB0 [pin 18] - PB1 [pin 19] - PB10 [pin 21] - PB11 [pin 22] - PB12 [pin 25] - PB13 [pin 26] - PB14 [pin 27] - PB15 [pin 28] - PB2 [pin 20] - PB3 [pin 39] - PB4 [pin 40] - PB5 [pin 41] - PB6 [pin 42] - PB7 [pin 43] - PB8 [pin 45] - PB9 [pin 46] - PC13 [pin 2] - PC14-OSC_IN [pin 3] - PC15-OSC32_OUT [pin 4] - PH0-OSC_IN [pin 5] - PH1-OSC_OUT [pin 6] - VDD [pin 48] - VDD [pin 24] - VDD [pin 1] - VDD_USB [pin 36] - VDDA [pin 9] - VSS [pin 47] - VSS [pin 35] - VSS [pin 23] - VSSA [pin 8] ### U2 — [BQ24040DSQT](https://www.flux.ai/lcsc/bq24040dsqt.md) - Role Details: Charger IC with power-path management - Package or Case Code: WSON-10_L2.0-W2.0-P0.40-TL-EP - LCSC Part Number: C2876332 - Manufacturer Part Number: BQ24040DSQT - Manufacturer Name: TI(德州仪器) - Role: Charger IC - JLCPCB Part Class: Extended Part - Part Type: Battery Management ICs **Pins:** - ~{CHG} [pin 8] - ~{PG} [pin 5] - EP [pin 11] - IN [pin 1] - ISET [pin 2] - ISET2 [pin 7] - NC [pin 6] - OUT [pin 10] - PRETERM [pin 4] - TS [pin 9] - VSS [pin 3] ### U3 — [TLV70033DDCT](https://www.flux.ai/lcsc/tlv70033ddct.md) - Manufacturer Name: TI(德州仪器) - Manufacturer Part Number: TLV70033DDCT - Role: 3.3 V regulator - Role Details: Low quiescent current LDO for 3.3 V rail - Package or Case Code: SOT-23-5_L2.9-W1.6-P0.95-LS2.8-BR - Part Type: Linear Voltage Regulators (LDO) - JLCPCB Part Class: Extended Part - LCSC Part Number: C2877582 **Pins:** - EN [pin 3] - GND [pin 2] - IN [pin 1] - N/C [pin 4] - OUT [pin 5] ### U4 — [Adafruit SPI TFT LCD Display Touch ILI9341](https://www.flux.ai/jharwinbarrozo/adafruit-spi-tft-lcd-display-touch-ili9341.md) - Role Details: 2.8" SPI TFT display module with touch interface - Manufacturer Name: Adafruit Industries - Role: Display Device - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Display Device - Datasheet URL: https://cdn-shop.adafruit.com/datasheets/ILI9341.pdf - Manufacturer Part Number: Adafruit ILI9341 **Pins:** - CS [pin 12] - D/C [pin 10] - GND [pin 13] - LED [pin 7] - MISO [pin 6] - MOSI [pin 9] - RESET [pin 11] - SCK [pin 8] - SD_CS [pin SD4] - SD_MISO [pin SD2] - SD_MOSI [pin SD3] - SD_SCK [pin SD1] - T_CLK [pin 5] - T_CS [pin 4] - T_DIN [pin 3] - T_DO [pin 2] - T_IRQ [pin 1] - VCC [pin 14] ### U5 — [MCP100-300D](https://www.flux.ai/vasy_skral/mcp100-300d.md) - Part Type: Integrated Circuit - Manufacturer Name: Microchip Technology - Role Details: Supervisory reset for 3.3 V rail to hold MCU in reset below threshold - Role: Undervoltage Lockout - Datasheet URL: http://www.microchip.com/mymicrochip/filehandler.aspx?ddocname=en011327 - Manufacturer Part Number: MCP100-300DI/TO **Pins:** - ~RST [pin 1] - VDD [pin 2] - VSS [pin 3] ### U6 — [TPS22917DBV](https://www.flux.ai/kicad-part-library/tps22917dbv.md) - Role: Overcurrent Protection - Manufacturer Part Number: TPS22917DBV - Manufacturer Name: Texas Instruments Inc. - Role Details: High-side load switch for USB-C 5 V rail with current limiting - Datasheet URL: http://www.ti.com/lit/ds/symlink/tps22917.pdf - Package or Case Code: SOT-23-6 **Pins:** - CT [pin 4] - GND [pin 2] - ON [pin 3] - QOD [pin 5] - VIN [pin 1] - VOUT [pin 6] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/simon26/voluntary-lavender-t-800](https://www.flux.ai/simon26/voluntary-lavender-t-800).* --- *Generated from [https://www.flux.ai/simon26/voluntary-lavender-t-800](https://www.flux.ai/simon26/voluntary-lavender-t-800)*