uwb-rescue-locator
Lucas-Poulos
Components (50)
| Reference | Value | Description |
|---|---|---|
| Q1 | AO3401A | |
| U1 | MCP73871 | |
| U2 | MAX17048G+T10 | |
| U3 | BT840 | Nordic nRF52840 BLE module, host for the 4x DW3210 anchor array and the BLE link to a laptop. Pin data verified against Fanstel BT840/F/E/X/XE Ver 1.15 (Sep 2019) Pin Function table, extracted with pdftotext -raw. |
| U4-U7 | DW3210 | Anchor A0 CENTER -- two-way ranging with the tag, yields RANGE. Pin data verified against Qorvo DW3000 Datasheet v1.3 Table 2 (extracted with pdftotext -raw; -layout mangles that table).,Anchor A1 OUTER -- timestamps the tag transmission for TDoA against A0, yields DIRECTION. Pin data verified against Qorvo DW3000 Datasheet v1.3 Table 2 (extracted with pdftotext -raw; -layout mangles that table).,Anchor A2 OUTER -- timestamps the tag transmission for TDoA against A0, yields DIRECTION. Pin data verified against Qorvo DW3000 Datasheet v1.3 Table 2 (extracted with pdftotext -raw; -layout mangles that table).,Anchor A3 OUTER -- timestamps the tag transmission for TDoA against A0, yields DIRECTION. Pin data verified against Qorvo DW3000 Datasheet v1.3 Table 2 (extracted with pdftotext -raw; -layout mangles that table). |
| U8 | TPS62A02PDDCR | 2.5-5.5V in, 2A synchronous buck, adjustable output, SOT-23-6. See lib_symbols description and regulation_notes.md for full verification. |
| U9 | MAX-M10S | u-blox MAX-M10S GNSS receiver. Reports the bay station's own absolute position so relative UWB fixes can be georeferenced. UART to the BT840. Pin data verified against u-blox Data Sheet UBX-20035208 R02 Table 9 -- 17 of 18 pins match KiCad's symbol; pin 15 is Reserved in R02 but VIO_SEL in KiCad, check the current revision. VCC (8) and V_IO (7) MUST be tied together per the datasheet. |
| U10 | LIS3MDL | 3-axis magnetometer giving the antenna frame's heading. Without this, a GNSS fix cannot convert a frame-relative bearing into an absolute one. I2C, address 0x1C or 0x1E by SDO strap. Siting matters more than the part: keep well away from the DC-DC, the battery and any frame steel. |
| U11 | LIS2DH | 3-axis accelerometer. Primary job is tilt compensation for U10 -- a magnetometer only reads heading correctly when level, and this station is set down on varying terrain. Second job: detect the station being knocked or moved, which invalidates both the GNSS fix and the heading. I2C, address 0x18 or 0x19 by SDO strap. |
| BT1 | 3.7V Li-Ion (JST-PH pigtail) | |
| C1,C5 | 10uF | Bulk decoupling on the BT840's VDD (pin 9). Generic good practice, not a datasheet-specified value. |
| C2,C3,C20 | 4.7uF | TPS62A02 VIN decoupling, 4.7uF X7R per datasheet Table 8-2 recommended component (Murata GRM21BR71A475KA73L, 0805) -- sized 0805 rather than 0603 given the DC-bias-derating concern already flagged for power_bms.kicad_sch's C1 (10uF/0603). |
| C4 | 0.1uF | |
| C6,C7,C32,C34-C36 | 100nF | HF decoupling on the BT840's VDD (pin 9). Generic good practice.,U10 VDD decoupling. Standard practice; confirm counts against each part's own datasheet application circuit at wiring time.,U11 VDD decoupling. Standard practice; confirm counts against each part's own datasheet application circuit at wiring time.,U9 VCC (pin 8) decoupling. Standard practice; confirm counts against each part's own datasheet application circuit at wiring time.,U9 V_BCKP (pin 6) backup-supply decoupling. Standard practice; confirm counts against each part's own datasheet application circuit at wiring time. |
| C21 | 22uF | TPS62A02 +3V3_SYS output decoupling, 22uF X7R per datasheet Table 8-2 recommended component (Murata GRM21BZ71A226KE15L, 0805) and Table 8-3's recommended L=1uH/Cout=22uF combination for VOUT>=1.8V (the '++' proven-stable combination). |
| C22 | 120pF | Optional feedforward capacitor across R8 (FB divider top resistor), 120pF per datasheet's own Application Information note ('a feedforward capacitor reduces output ripple in PSM and improves load transient response; a 120pF capacitor is good for the 1.8V output typical application') -- included here since this rail also uses PSM, per the same design intent. |
| C24-C27 | 2200pF | AC coupling, TCXO/buffer output to DW3210 anchor 1 XTI (pin 21). 2200pF is the value recommended by DW3000 Datasheet v1.3 Table 10 for an external reference.,AC coupling, TCXO/buffer output to DW3210 anchor 2 XTI (pin 21). 2200pF is the value recommended by DW3000 Datasheet v1.3 Table 10 for an external reference.,AC coupling, TCXO/buffer output to DW3210 anchor 3 XTI (pin 21). 2200pF is the value recommended by DW3000 Datasheet v1.3 Table 10 for an external reference.,AC coupling, TCXO/buffer output to DW3210 anchor 4 XTI (pin 21). 2200pF is the value recommended by DW3000 Datasheet v1.3 Table 10 for an external reference. |
| C28-C31 | 1pF | XTO (pin 22) to GND on DW3210 anchor 1. Required only when an external clock is used, per the DW3000 Datasheet v1.3 pin table.,XTO (pin 22) to GND on DW3210 anchor 2. Required only when an external clock is used, per the DW3000 Datasheet v1.3 pin table.,XTO (pin 22) to GND on DW3210 anchor 3. Required only when an external clock is used, per the DW3000 Datasheet v1.3 pin table.,XTO (pin 22) to GND on DW3210 anchor 4. Required only when an external clock is used, per the DW3000 Datasheet v1.3 pin table. |
| C33 | 1uF | U9 bulk decoupling. Standard practice; confirm counts against each part's own datasheet application circuit at wiring time. |
| D1 | MBRA140T3G | |
| D2,D3 | ESD5B5.0ST1G | |
| D4-D7 | LED | Charge-complete LED -- driven from MCP73871 STAT2 (pin 7, power_bms.kicad_sch),Charging-status LED -- driven from MCP73871 STAT1 (pin 8, power_bms.kicad_sch),External-power-good LED -- driven from MCP73871 ~PG (pin 6, power_bms.kicad_sch),System status LED -- intended to be driven from a BT840 (nRF52840) GPIO (not yet allocated) |
| J1 | CUI PJ-063AH | |
| J2 | USB4125-GF-A | |
| J3 | Conn_ARM_JTAG_SWD_10 | ARM Cortex Debug SWD header for the BT840 (nRF52840). Same part as the wristband's J3 so one probe and cable serve both boards. |
| L1 | 1uH | Power inductor, 1uH, >=2A saturation current per TPS62A02 datasheet Table 8-3/Table 8-2 recommended component list -- e.g. Coilcraft XGL3520-102MEC (2A-rated) or Murata DFE252012F-1R0M (1A-rated, only if using the 1A TPS62A01 variant instead). No exact KiCad default footprint match found for XGL3520; pick exact footprint/PN at BOM time. |
| R1,R9,R25-R28 | 100k | IRQ/GPIO8 (DW3210 pin 1) pull-down for anchor A0, per Qorvo Figure 11, 'to prevent spurious interrupts'. The datasheet also notes IRQ floats in SLEEP/DEEPSLEEP and recommends 100k externally.,IRQ/GPIO8 (DW3210 pin 1) pull-down for anchor A1, per Qorvo Figure 11, 'to prevent spurious interrupts'. The datasheet also notes IRQ floats in SLEEP/DEEPSLEEP and recommends 100k externally.,IRQ/GPIO8 (DW3210 pin 1) pull-down for anchor A2, per Qorvo Figure 11, 'to prevent spurious interrupts'. The datasheet also notes IRQ floats in SLEEP/DEEPSLEEP and recommends 100k externally.,IRQ/GPIO8 (DW3210 pin 1) pull-down for anchor A3, per Qorvo Figure 11, 'to prevent spurious interrupts'. The datasheet also notes IRQ floats in SLEEP/DEEPSLEEP and recommends 100k externally.,TPS62A02 feedback divider, bottom resistor (FB to GND). R2 = 100k per datasheet's own worked example and its 'R2 must not be higher than 100k for acceptable noise sensitivity' guidance -- used at exactly the recommended ceiling value. |
| R2 | 2.00k | |
| R3 | 20.0k | |
| R4 | 330k | |
| R5 | 110k | |
| R6,R7 | 5.1k | |
| R8 | 453k | TPS62A02 feedback divider, top resistor (VOUT to FB). R1 = R2 x (VOUT/VFB - 1) = 100k x (3.3V/0.6V - 1) = 450k per datasheet Eq.2 -- 453k is the nearest standard E96 1% value (100k x 4.53), giving VOUT = 0.6V x (1 + 453k/100k) = 3.318V. |
| R10-R17 | 10k | GPIO5 SPI-mode strap pull-down for anchor A0 (DW3210 pin 5). Defines SPI mode 0 at power-up, per the DW3000 'Sample GPIOs 5&6 to set SPI mode' step in Figures 1 and 2.,GPIO5 SPI-mode strap pull-down for anchor A1 (DW3210 pin 5). Defines SPI mode 0 at power-up, per the DW3000 'Sample GPIOs 5&6 to set SPI mode' step in Figures 1 and 2.,GPIO5 SPI-mode strap pull-down for anchor A2 (DW3210 pin 5). Defines SPI mode 0 at power-up, per the DW3000 'Sample GPIOs 5&6 to set SPI mode' step in Figures 1 and 2.,GPIO5 SPI-mode strap pull-down for anchor A3 (DW3210 pin 5). Defines SPI mode 0 at power-up, per the DW3000 'Sample GPIOs 5&6 to set SPI mode' step in Figures 1 and 2.,GPIO6 SPI-mode strap pull-down for anchor A0 (DW3210 pin 2). Defines SPI mode 0 at power-up, per the DW3000 'Sample GPIOs 5&6 to set SPI mode' step in Figures 1 and 2.,GPIO6 SPI-mode strap pull-down for anchor A1 (DW3210 pin 2). Defines SPI mode 0 at power-up, per the DW3000 'Sample GPIOs 5&6 to set SPI mode' step in Figures 1 and 2.,GPIO6 SPI-mode strap pull-down for anchor A2 (DW3210 pin 2). Defines SPI mode 0 at power-up, per the DW3000 'Sample GPIOs 5&6 to set SPI mode' step in Figures 1 and 2.,GPIO6 SPI-mode strap pull-down for anchor A3 (DW3210 pin 2). Defines SPI mode 0 at power-up, per the DW3000 'Sample GPIOs 5&6 to set SPI mode' step in Figures 1 and 2. |
| R29-R32 | 1k | Series resistor for D4 (STAT1).,Series resistor for D5 (STAT2).,Series resistor for D6 (~PG).,Series resistor for D7 system-status LED. |
| SW2 | RESET | Reset button, pulling the BT840's active-low reset to ground. Footprint to be chosen at BOM time, same as the previous revision. |
| TH1 | 10k NTC | |
| TP1 | +3V3_SYS | Regulated 3.3V rail from the TPS62A02 (regulation.kicad_sch). Check first when anything misbehaves. |
| TP2 | +VSYS | Unregulated system rail out of the MCP73871 power path (power_bms.kicad_sch). |
| TP3,TP4 | GND | General-purpose ground, placed away from the clock area.,Scope ground, to be placed adjacent to TP5-TP9. Use a short ground spring here, not a flying clip lead -- at 38.4MHz the lead inductance distorts the measurement. |
| TP5 | REF_38M4 | TCXO output, before the fan-out buffer. Confirms the shared reference exists and is on frequency at all. |
| TP6 | CLK_A0 | Buffer output to the A0 (center) DW3210 XTI pin. |
| TP7 | CLK_A1 | Buffer output to the A1 DW3210 XTI pin. |
| TP8 | CLK_A2 | Buffer output to the A2 DW3210 XTI pin. |
| TP9 | CLK_A3 | Buffer output to the A3 DW3210 XTI pin. |
| TP10 | SPI_SCLK | Shared SPI clock to all four anchors. Must be on SPIM3 -- the only high-speed SPI instance on the nRF52840. |
| TP11 | SPI_MOSI | Shared SPI MOSI to all four anchors. |
| TP12 | SPI_MISO | Shared SPI MISO from all four anchors. |
| TP13 | IRQ_A0 | Interrupt from the A0 center anchor. Makes the ranging exchange timing visible on a scope. |
| TP14 | ANCHOR_RSTn | Shared reset to all four DW3210s. |