Accordion M1
ESH10000597 · Rev R1
Generated 2026-06-05 18:18 UTC
Accordion M1 main board — R1. Successor to R0 prototype (id=13). USB-C PD 20V input, TPS259474 E-Fuse protection, regulated outputs 5V/12V/3.3V/2.5V/1.8V/2.5VREF. Module connectors: SO-DIMM (J9), M2 (J15), N-Top (J10/J11/J12), Comtop (J3). I2C bus mux, ADC monitoring, fan control, LED driver, RTC. Hammond enclosure.
Coverage
0%
Done
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Requirements
0
Test Cases
42
Records
0
Requirements
| Code | Status | Category | Title | Statement | Acceptance |
|---|---|---|---|---|---|
| REQ-001 | draft | Functional | USB-C 20V PD primary power input | The design shall accept USB-C 20V PD as primary power input. | VIN at U10 input = 20V ±5% with USB-C 20V supply connected. |
| REQ-002 | draft | Functional | E-Fuse U10 (VDD) OVLO trip point >21V | E-Fuse U10 (VDD) OVLO divider shall be set with trip point >21V. | OVLO does not trip at 20V; U10 output live at nominal input voltage. |
| REQ-003 | draft | Functional | E-Fuse U16 (5V) OVLO trip point >5.5V | E-Fuse U16 (5V) OVLO divider shall be set with trip point >5.5V. | OVLO does not trip at 5V; U16 output live at nominal 5V rail. |
| REQ-004 | draft | Functional | E-Fuse current limit 5A via R39 = 680Ω | E-Fuse current limit (ILIM) shall be set to 5A via R39 = 680Ω. | U10 trips at 5A ±10%; verify with load sweep. |
| REQ-005 | draft | Functional | E-Fuse dVdT ramp configuration | E-Fuse dVdT ramp shall be correctly configured on all E-Fuses. | R1/R19/R63 = 0Ω; C24/C46/C51 = 330pF; output ramp verified against datasheet. |
| REQ-006 | draft | Performance | 5V regulated rail stable under load | 5V regulated rail shall be present and stable under load. | 5V rail = 5.0V ±3% from no-load to rated load. |
| REQ-007 | draft | Performance | 3.3V regulated rail stable | 3.3V regulated rail shall be present and stable. | 3.3V rail = 3.3V ±3%. |
| REQ-008 | draft | Performance | 2.5V regulated rail stable | 2.5V regulated rail shall be present and stable. | 2.5V rail = 2.5V ±3%. |
| REQ-009 | draft | Performance | 1.8V regulated rail stable | 1.8V regulated rail shall be present and stable. | 1.8V rail = 1.8V ±3%. |
| REQ-010 | draft | Performance | Precision voltage reference 2.500V | Precision voltage reference shall output 2.500V. | VREF = 2.500V ±0.05%. |
| REQ-011 | draft | Functional | 5V to RPi via R147; Q8 circuit removed | 5V to RPi shall be routed via R147; Q8 circuit shall be removed. | Q8 and associated components absent from schematic and BOM; 5V present at RPi via R147. |
| REQ-012 | draft | Interface | RPi 3V3 output routed as net RPI_ON | RPi 3V3 output (M1 pin 1) shall be routed as net RPI_ON. | Net RPI_ON present in schematic connected to M1 pin 1; routed in layout. |
| REQ-013 | draft | Functional | [TBD] 12V rail inclusion decision | [TBD] 12V rail inclusion for R1 shall be decided. | Decision required: include or remove 12V rail. See DL-022. |
| REQ-014 | draft | Functional | [TBD] PoE input strategy decision | [TBD] PoE input strategy for R1 shall be decided. | Decision required: keep/remove PoE; if kept — active or passive; 45W or 90W. See DL-023. |
| REQ-015 | draft | Manufacturing | Bulk capacitors fabricator-compatible | Bulk capacitors shall use a part compatible with the fabricator's assembly process. | Bulk cap part confirmed mountable by fabricator; no assembly issue. |
| REQ-016 | draft | Functional | Push button S1 toggles system power on/off | Push button S1 shall toggle system power on/off. | Press S1: system powers on (U10 output live); press S1 again: system powers off (U10 output = 0V). |
| REQ-017 | draft | Functional | Power enable via pin-strap without MCU firmware | Power enable shall be achievable via pin-strap without MCU firmware. | A defined pin-strap (jumper or resistor strap) bypasses MCU and enables system power for bring-up. |
| REQ-018 | draft | Functional | [TBD] Push button / power-on MCU decision | [TBD] Push button / power-on management by MCU shall be decided. | Decision required: ESP32 or ATtiny 3227; define scope of MCU functions. See DL-025. |
| REQ-019 | draft | Mechanical | PCB fits and mounts in Hammond enclosure | PCB shall fit and mount correctly in Hammond enclosure. | PCB mounts in enclosure with all standoffs engaged; no mechanical interference. |
| REQ-020 | draft | Mechanical | N-Top fixation screws no protrusion into SO-DIMM zone | N-Top module fixation screws shall not protrude into SO-DIMM clearance zone. | M3×16mm screws used; no protrusion below PCB into J9 clearance zone. |
| REQ-021 | draft | Mechanical | SO-DIMM connector J9 seats with latch engagement | SO-DIMM connector (J9) shall seat correctly with latch engagement. | SO-DIMM module seats and latches without force. |
| REQ-022 | draft | Mechanical | M2 slot J15 seats and screws correctly | M2 slot (J15) shall seat and screw down correctly. | M2 module seats and screws down; no interference with adjacent connectors. |
| REQ-023 | draft | Mechanical | Comtop connector J3 seats correctly | Comtop connector (J3) shall seat correctly. | Comtop module seats correctly. |
| REQ-024 | draft | Mechanical | Back panel fan screws no collision with PCB edge | Back panel fan screws shall not collide with PCB edge. | All four fan screws mounted with back panel installed; no collision with PCB. |
| REQ-025 | draft | Mechanical | Standoff heights defined for both assembly variants | Standoff heights shall be defined for both comm-top and no-comm-top assembly variants. | Assembly BOM specifies standoff part number and height for each variant. |
| REQ-026 | draft | Mechanical | RPi header no perceptible rattling when mated | RPi header shall have no perceptible rattling when mated. | RPi header mated; no rattle observed when device is handled. |
| REQ-027 | draft | Mechanical | RPi connectors flush with or recessed behind front panel | RPi connectors shall be flush with or recessed behind the front panel surface. | RPi connectors do not protrude beyond front panel outer face; measured ≤0mm protrusion. |
| REQ-028 | draft | Mechanical | Panel break tab mouse bites on PCB side | Panel break tab mouse bites shall be on the PCB side. | All break tab mouse bites located on PCB side; clean PCB edge after depanelling. |
| REQ-029 | draft | Functional | Silkscreen reads 'Accordion M1' | Silkscreen shall read 'Accordion M1'. | Silkscreen text confirmed 'Accordion M1' in Gerber/fabrication files. |
| REQ-030 | draft | Functional | U3 silkscreen pin-1 / polarity marker | U3 silkscreen shall include a visible pin-1 / polarity marker. | Pin-1 dot or polarity indicator for U3 visible in silkscreen. |
| REQ-031 | draft | Functional | I2C devices 7-bit address annotated in schematic | All I2C-addressed devices shall have their 7-bit address annotated in the schematic. | Every I2C device on the schematic has a text annotation showing its resulting 7-bit address. |
| REQ-032 | draft | Functional | I2C bus mux channels Ch0–Ch4 functional | I2C bus mux channels Ch0–Ch4 shall be functional. | I2C scan on each channel returns ACK from all expected devices. |
| REQ-033 | draft | Functional | R23 non-mounted to configure ADS7828 at 0x49 | R23 shall be non-mounted (NM) to configure ADS7828 address to 0x49. | R23 absent from BOM and PCB; ADS7828 responds at 0x49. |
| REQ-034 | draft | Interface | UART GPIO routing per ESH10000539 R1 | UART GPIO routing shall match the correct RPi UART pin assignment per ESH10000539 R1. | M2TxD and M2RxD routed to correct RPi GPIO pins per ESH10000539 R1; UART communication functional on D.06. |
| REQ-035 | draft | Functional | Pull-up resistors 4.7kΩ on UART nets at J9 | Pull-up resistors (4.7kΩ to 3V3) shall be present on M2TxD, M2RxD, M2RTS, M2CTS. | Pull-up resistors present on all four UART nets at J9; confirmed in schematic and BOM. |
| REQ-036 | draft | Interface | T1DATA[0:95] bidirectional bus routes correctly | SO-DIMM ↔ N-Top bidirectional data bus T1DATA[0:95] shall route correctly in both directions. | All 96 signals toggle correctly in both directions. |
| REQ-037 | draft | Interface | SPI connectivity to SO-DIMM J9 functional | SPI connectivity to SO-DIMM J9 shall be functional (SPI0_SCK, MOSI, MISO, CS0_N, CS1_N). | Correct SPI response received for both CS lines. |
| REQ-038 | draft | Interface | UART connectivity to SO-DIMM J9 functional | UART connectivity to SO-DIMM J9 shall be functional (M2TxD, M2RxD, M2RTS, M2CTS). | Known data pattern transmitted and received correctly in both directions. |
| REQ-039 | draft | Interface | [TBD] MCU signals routed to module slots | [TBD] MCU signals shall be routed to module slots as decided. | Decision required: which slots and which signal types. See DL-026. |
| REQ-040 | draft | Performance | U24 voltage monitoring within ±5% of actual | U24 (AD5593R) voltage monitoring channels shall read within ±5% of actual rail voltage. | MON_VIN, MON_12V, MON_5V, MON_VPOE, MON_VBUS ADC readings within ±5% of true rail voltages. |
| REQ-041 | draft | Performance | U24 current monitoring within ±10% of actual | U24 current monitoring channels shall read within ±10% of actual current. | MON_IIN, MON_C12V, MON_C5V ADC readings within ±10% of known applied currents. |
| REQ-042 | draft | Functional | MON_12V and MON_5V dividers no ADC saturation | MON_12V and MON_5V voltage dividers shall not saturate the ADC at nominal rail voltages. | Scaled voltage at ADC input ≤2.5V (ADC reference) with rail at nominal; R145 and R146 = 2kΩ. |
| REQ-043 | draft | Functional | Fan controller U21 regulates fan speed via I2C | Fan controller U21 (MAX6650) shall regulate fan speed via I2C. | Fan runs at full speed at boot; speed reduces to regulated level when accordion process is running. |
| REQ-044 | draft | Functional | LED driver LP5012 controllable via I2C | LED driver LP5012 shall be controllable via I2C. | All LED channels respond to brightness commands (off / full / mid) via I2C. |
| REQ-045 | draft | Functional | RTC and battery backup excluded from R1 | RTC (PCF8523) and battery backup shall NOT be included in R1. | U32, battery connector, and all associated passives absent from schematic, BOM, and layout. |
| REQ-046 | draft | Manufacturing | ≤40 unique component types per PCB side | Design shall use no more than 40 unique component types per PCB side. | BOM unique component count per side ≤40 at time of layout sign-off. |
Test Cases
| Code | Status | Category | Title / Signal | Target | Pass Criterion | Linked REQ |
|---|---|---|---|---|---|---|
| TC-A-00 | open | performance | U24 voltage monitoring accuracy ±5% | — | MON_VIN, MON_5V, MON_VBUS ADC readings within ±5% of true rail voltages measured simultaneously with calibrated DVM. | REQ-040 |
| TC-A-01 | open | performance | U24 current monitoring accuracy ±10% | — | MON_IIN, MON_C5V ADC readings within ±10% of known applied currents; current set with calibrated programmable load. | REQ-041 |
| TC-A-02 | open | functional | MON_12V and MON_5V divider — no ADC saturation | — | Scaled voltage at U24 ADC input ≤2.5V with 5V rail at nominal; R145 and R146 = 2kΩ confirmed in BOM; ADC raw counts below full-scale. | REQ-042 |
| TC-D-00 | open | functional | I2C bus mux channels Ch0–Ch4 functional | — | I2C scan on each of Ch0–Ch4 with correct channel selected; all expected devices ACK; no ghost addresses. | REQ-032 |
| TC-D-01 | open | functional | R23 NM — ADS7828 responds at 0x49 | — | R23 absent from assembled board; I2C scan returns ACK at address 0x49 (ADS7828); no response at other ADS7828 addresses. | REQ-033 |
| TC-D-02 | open | functional | UART GPIO routing per ESH10000539 R1 | — | M2TxD and M2RxD traced to correct RPi GPIO pins per ESH10000539 R1 schematic; UART loopback test passes (known pattern sent and received correctly). | REQ-034 |
| TC-D-03 | open | functional | UART net pull-up resistors at J9 | — | 4.7kΩ pull-up resistors to 3V3 present on M2TxD, M2RxD, M2RTS, M2CTS at J9; confirmed in schematic BOM audit and net continuity. | REQ-035 |
| TC-D-04 | open | functional | T1DATA[0:95] bidirectional bus signal routing | — | All 96 T1DATA signals toggle correctly in both SO-DIMM→N-Top and N-Top→SO-DIMM directions; verified via loopback or signal-level test. | REQ-036 |
| TC-D-05 | open | functional | SPI connectivity to SO-DIMM J9 | — | SPI0_SCK, MOSI, MISO, CS0_N, CS1_N connected to J9; correct SPI response received for both CS lines with a known SPI peripheral. | REQ-037 |
| TC-D-06 | open | functional | UART connectivity to SO-DIMM J9 | — | M2TxD, M2RxD, M2RTS, M2CTS at J9; known data pattern transmitted and received correctly in both directions. | REQ-038 |
| TC-K-00 | open | functional | Silkscreen reads 'Accordion M1' | — | Silkscreen text 'Accordion M1' confirmed in Gerber output and fabrication files before ordering. | REQ-029 |
| TC-K-01 | open | functional | U3 pin-1 / polarity marker in silkscreen | — | Pin-1 dot or polarity arrow for U3 visible and correctly oriented in silkscreen layer of Gerber/fabrication files. | REQ-030 |
| TC-K-02 | open | functional | I2C device 7-bit address annotations in schematic | — | Every I2C-addressed device on the schematic has a text annotation showing its resulting 7-bit address; confirmed by schematic review. | REQ-031 |
| TC-M-00 | open | functional | PCB fit and mounting in Hammond enclosure | — | PCB mounts in Hammond enclosure with all standoffs engaged; lid closes; no mechanical interference at any connector or edge. | REQ-019 |
| TC-M-01 | open | functional | N-Top fixation screws — no SO-DIMM zone protrusion | — | M3×16mm screws installed; visual and physical inspection confirms no screw tip protrudes below PCB into J9 clearance zone. | REQ-020 |
| TC-M-02 | open | functional | SO-DIMM connector J9 seating and latch | — | SO-DIMM module inserted and latches correctly without excessive force; latch engagement confirmed on both sides. | REQ-021 |
| TC-M-03 | open | functional | M2 slot J15 seating and screw-down | — | M2 module seats fully; M2 screw engages standoff; no interference with adjacent connectors. | REQ-022 |
| TC-M-04 | open | functional | Comtop connector J3 seating | — | Comtop module seats correctly; no interference with adjacent components or PCB edge. | REQ-023 |
| TC-M-05 | open | functional | Back panel fan screws — no PCB edge collision | — | All four fan screws installed with back panel; no screw contacts PCB edge; confirmed by physical inspection. | REQ-024 |
| TC-M-06 | open | functional | Standoff heights — both assembly variants in BOM | — | Assembly BOM lists standoff part number and height for both comm-top and no-comm-top variants; confirmed in BOM audit. | REQ-025 |
| TC-M-07 | open | functional | RPi header — no rattle when mated | — | RPi module mated to header; device handled and tilted; no perceptible rattle from RPi header connection. | REQ-026 |
| TC-M-08 | open | functional | RPi connectors flush with or recessed behind front panel | — | Front panel installed; RPi connector faces measured; protrusion beyond outer face ≤0mm. | REQ-027 |
| TC-M-09 | open | functional | Panel break tab mouse bites on PCB side | — | All panel break tabs depanelled; mouse bites confirmed on PCB side only; no bites on panel side; clean PCB edge. | REQ-028 |
| TC-MF-00 | open | functional | Bulk capacitors fabricator assembly compatibility | — | Bulk capacitor part number confirmed mountable by fabricator; assembly confirmation received before PCB order placed. | REQ-015 |
| TC-MF-01 | open | functional | ≤40 unique component types per PCB side | — | BOM unique component count per PCB side ≤40 at layout sign-off; verified by BOM audit before fabrication release. | REQ-046 |
| TC-P-00 | open | functional | USB-C 20V PD input voltage at U10 | — | VIN at U10 input pin = 20V ±5% (19.0–21.0V) with USB-C 20V PD supply connected. | REQ-001 |
| TC-P-01 | open | functional | U10 VDD E-Fuse output and OVLO verification | — | U10 output live at 20V nominal input; OVLO does not trip below 21V; trips above 21V threshold. | REQ-002 |
| TC-P-02 | open | functional | U16 5V E-Fuse output and OVLO verification | — | U16 output live at 5V nominal; OVLO does not trip below 5.5V; trips above 5.5V threshold. | REQ-003 |
| TC-P-03 | open | performance | E-Fuse ILIM current trip at 5A | — | U10 current limit trips at 5A ±10% (4.5–5.5A) during load sweep; confirmed via load step or programmable load. | REQ-004 |
| TC-P-04 | open | functional | E-Fuse dVdT ramp component audit | — | R1/R19/R63 = 0Ω confirmed in BOM and schematic; C24/C46/C51 = 330pF confirmed; output ramp time within datasheet range. | REQ-005 |
| TC-P-05 | open | performance | 5V regulated rail stability under load | — | 5V rail = 5.0V ±3% (4.85–5.15V) from no-load to rated load. | REQ-006 |
| TC-P-06 | open | performance | 3.3V regulated rail voltage | — | 3.3V rail = 3.3V ±3% (3.20–3.40V) at nominal load. | REQ-007 |
| TC-P-07 | open | performance | 2.5V regulated rail voltage | — | 2.5V rail = 2.5V ±3% (2.43–2.58V) at nominal load. | REQ-008 |
| TC-P-08 | open | performance | 1.8V regulated rail voltage | — | 1.8V rail = 1.8V ±3% (1.75–1.85V) at nominal load. | REQ-009 |
| TC-P-09 | open | performance | Precision voltage reference 2.500V accuracy | — | VREF = 2.500V ±0.05% (2.4988–2.5013V) measured with calibrated DVM. | REQ-010 |
| TC-P-10 | open | functional | 5V to RPi via R147; Q8 circuit absent | — | Q8 and associated components absent from schematic and BOM; 5V measured at RPi via R147 with system powered. | REQ-011 |
| TC-P-11 | open | functional | RPI_ON net schematic and layout routing | — | Net RPI_ON present in schematic connected to M1 pin 1; continuity confirmed in layout/netlist. | REQ-012 |
| TC-S-00 | open | functional | Fan controller U21 (MAX6650) speed regulation via I2C | — | Fan runs at full speed at boot; I2C command to accordion process causes fan speed to reduce to regulated target; speed confirmed via tachometer or MAX6650 count register. | REQ-043 |
| TC-S-01 | open | functional | LED driver LP5012 brightness control via I2C | — | All LED channels respond to brightness commands: off (0%), mid (~50%), full (100%); no channels stuck or non-responsive. | REQ-044 |
| TC-S-02 | open | functional | RTC (PCF8523) and battery backup absent | — | U32, battery connector, and associated passives absent from schematic, BOM, and assembled board; I2C scan confirms no ACK at 0x68 (PCF8523 address). | REQ-045 |
| TC-SW-00 | open | functional | Push button S1 power on/off toggle | — | Press S1: U10 output goes live (system powered on); press S1 again: U10 output = 0V (system off). Both transitions confirmed. | REQ-016 |
| TC-SW-01 | open | functional | Pin-strap bring-up power enable (no MCU) | — | With pin-strap applied (jumper or resistor strap as defined), system power enabled without MCU firmware present; U10 output live at 20V. | REQ-017 |
Verification Records
No verification records.
Design Rule Status
■ No violations ■ Warning ■ Error ■ Waived