Here are the issues observed directly in your schematic, organized by category, with actionable corrections: ## 1. Electrical and Logical Issues - **Missing I²C pull-ups** The I²C bus lines lack pull-up resistors (R5 and R16 are series resistors, not pull-ups). → Add two 4.7 kΩ pull-ups on SDA and SCL, e.g.: - [4.7k Resistor](https://www.flux.ai/search?type=components&q=4.7k%20Resistor) for SCL - [4.7k Resistor](https://www.flux.ai/search?type=components&q=4.7k%20Resistor) for SDA - **No CAN bus termination** The CAN transceiver [U7](https://www.flux.ai/:handle/:documentSlug?fit=U7) has only a series resistor [R6](https://www.flux.ai/:handle/:documentSlug?fit=R6) on CAN_H. There is no 120 Ω termination across CAN_H/CAN_L. → Add a [120Ω Resistor](https://www.flux.ai/search?type=components&q=120Ω%20Resistor) between CAN_H and CAN_L. - **No RS-485 termination or failsafe** The RS-485 transceiver [U5](https://www.flux.ai/:handle/:documentSlug?fit=U5) has no 120 Ω termination resistor between A and B and no bias resistors for failsafe. → Add a [120Ω Resistor](https://www.flux.ai/search?type=components&q=120Ω%20Resistor) across A/B, plus two [4.7k Resistor](https://www.flux.ai/search?type=components&q=4.7k%20Resistor) bias resistors (pull-up on A, pull-down on B). - **Shared RESET/EN net** [R29](https://www.flux.ai/:handle/:documentSlug?fit=R29) pulls up together: - [U4](https://www.flux.ai/:handle/:documentSlug?fit=U4) EN - [U3](https://www.flux.ai/:handle/:documentSlug?fit=U3) ~RESET - Display reset ([U20](https://www.flux.ai/:handle/:documentSlug?fit=U20)) Tying these functions together can cause unintended resets or keep-alive behavior. → Split into two nets with separate pull-ups: one resistor for EN, one for ~RESET/display RESET. --- ## 2. Component-Level Review - **Local decoupling missing on level translator** [U1](https://www.flux.ai/:handle/:documentSlug?fit=U1) (TXS0102) needs a 0.1 µF cap on both VCCA and VCCB, placed close to its pins. → Add two [100 nF Capacitor](https://www.flux.ai/search?type=components&q=100nF%20Capacitor). - **Decoupling missing on CAN and RS-485 transceivers** Neither [U7](https://www.flux.ai/:handle/:documentSlug?fit=U7) nor [U5](https://www.flux.ai/:handle/:documentSlug?fit=U5) have a local bypass capacitor. → Place a [100 nF Capacitor](https://www.flux.ai/search?type=components&q=100nF%20Capacitor) adjacent to each VCC pin. - **LDO decoupling values** [U6](https://www.flux.ai/:handle/:documentSlug?fit=U6) (AMS1117-3.3) has C3/C4 = 22 µF (6.3 V) and C6 = 10 µF. The datasheet calls for 10 µF minimum. Using 22 µF is acceptable, but ensure the voltage rating ≥ 10 V. - **LED current-limits** [LED1](https://www.flux.ai/:handle/:documentSlug?fit=LED1) channels each have series resistors [R1](https://www.flux.ai/:handle/:documentSlug?fit=R1), [R4](https://www.flux.ai/:handle/:documentSlug?fit=R4), [R17](https://www.flux.ai/:handle/:documentSlug?fit=R17). Verify their values suit your target LED current. --- ## 3. Power and Signal Integrity - **Star-ground recommended** Multiple ground portals are scattered across the schematic. For best noise performance, tie all analog/digital ground returns to a single star-point. - **Power‐rail annotations** Clearly label 5 V vs. 3.3 V rails (instead of generic net names) so decoupling and protection components are unambiguous. --- ## 4. Schematic Best Practices - **Unnamed nets** Many nets show as “Net 1”, “Net 4”, etc. Replace with descriptive labels (e.g. “SPI_SCK”, “VBUS_IN”) for readability. - **RouteBranchPoint clutter** The “RouteBranchPoint” symbols add visual noise. Use junction dots on multi-pin nets or explicit net labels instead. - **Consistent net naming** Ensure all connectors, modules, and ports use the same net names across the schematic (e.g. `CAN_H`, `CAN_L`, `SDA`, `SCL`) to avoid confusion. --- Addressing the above will strengthen power stability, bus reliability, and overall clarity of your design.