outputs¶
Subsystem sheet /outputs of camera-gpio-interface-pcb, from the board recipe subsystems/outputs.subsystem.yaml.
The four 3.3 V BNC outputs to the Neuropixels OneBox: SYNC OUT from its own SN74LVC1G125 driver on SYNC_IN through 470 Ω, and the three CAMn OUT lines the camera channels drive through their own 470 Ω; two USBLC6 clamps across the four jacks, referenced to +5V; an activity LED and the InstrumentPort tap on SYNC OUT.
Board note: board-authored sheet, 12 parts
Notes¶
- Fixed at 3.3 V: the OneBox ADC inputs are high impedance with a ±5 V range, and anything fed back into a pyControl BNC must stay under that board's 3.3 V clamps. 470 Ω (0603, 1/10 W) rather than 50 Ω: a shorted BNC costs 7 mA, and a OneBox DAC left switched in on the shared pin holds the node at the clamp (about −0.8 V or +5.5 V) for 12 mA through the driver and 64 mW in the resistor, inside both ratings. Into a ~1 MΩ ADC input the resistor costs 0.05 % of amplitude and about 140 ns of edge.
- U401 (SN74LVC1G125, ~OE to ground) drives SYNC_OUT from SYNC_IN, a driver of its own so a fault on the OneBox cable cannot disturb the three camera drivers that share SYNC_IN; R402 (470 Ω) makes SYNC_OUT_BNC at J401. The CAMn_OUT_BNC nets arrive from the camera blocks already behind their 470 Ω and meet only their jacks and the clamps here: J402 CAM1, J403 CAM2, J404 CAM3.
- USBLC6-2P6 is a two-line array (pins 1/6 one node, 3/4 the other): U402 pairs CAM1 OUT with CAM2 OUT and U403 CAM3 OUT with SYNC OUT, VBUS on +5V. C401 decouples U401; U401 pin 5 is the package's NC pin, left open.
- D401 through R401 (680 Ω) shows activity on SYNC_OUT. R403 (100 Ω) taps SYNC_OUT to SYNC_OUT_INST (DIG2) at the driver output before the 470 Ω, so the InstrumentPort sees what the BNC carries.
Ports¶
The recipe's ports as the sheet symbol carries them, the root label each meets, and the net's class, MCU pin and meaning.
| Port | Shape | Wired to | Net | Class | GPIO | Meaning | |
|---|---|---|---|---|---|---|---|
+3.3V |
passive | shared | +3.3V |
/+3.3V |
PWR_3V3_NARROW | The only logic rail, from the TPS73733 on the power sheet; always on while USB is present, as the InstrumentPort block requires | |
+5V |
passive | shared | +5V |
/+5V |
PWR_5V_NARROW | VBUS after the USB block's Schottky (+5V_USB in the design record): the Line 0 pull-ups and every ESD array's clamp reference | |
CAM1_OUT_BNC |
input | CAM1_OUT_BNC |
/CAM1_OUT_BNC |
Default | Camera 1 ExposureActive (Line 2, Schmitt-buffered) behind the block's 470 Ω, to the CAM1 OUT BNC | ||
CAM2_OUT_BNC |
input | CAM2_OUT_BNC |
/CAM2_OUT_BNC |
Default | Camera 2 ExposureActive (Line 2, Schmitt-buffered) behind the block's 470 Ω, to the CAM2 OUT BNC | ||
CAM3_OUT_BNC |
input | CAM3_OUT_BNC |
/CAM3_OUT_BNC |
Default | Camera 3 ExposureActive (Line 2, Schmitt-buffered) behind the block's 470 Ω, to the CAM3 OUT BNC | ||
GND |
passive | shared | GND |
/GND |
PWR_RETURN_LOCAL | Board ground; every BNC shell and camera pins 5 and 6 | |
SYNC_IN |
input | SYNC_IN |
/SYNC_IN |
Default | Conditioned Rsync from the SYNC IN BNC, 3.3 V, to the three Line 0 drivers and the SYNC OUT driver | ||
SYNC_OUT_INST |
input | SYNC_OUT_INST |
/SYNC_OUT_INST |
INSTRUMENT | DIG2: what the SYNC OUT BNC carries, at the driver output before the 470 Ω |
Blocks¶
The recipe's roles and the placements that fill them on this board.
| Role | Instance | Block | Lifecycle | Summary |
|---|---|---|---|---|
Glue¶
The subsystem's own parts and nets, drawn by the board around the blocks.
| References | Part | Value | Role |
|---|---|---|---|
C401 |
OW-CAP-100N-0402-X5R-16V |
100nF | U401 decoupling |
D401 |
OW-MISC-APHHS1005CGCK |
APHHS1005CGCK | SYNC OUT activity LED |
J401, J402, J403, J404 |
OW-CONN-HL-BNC-KHDA |
HL-BNC-KHDA | the output BNC jacks: J401 SYNC OUT, J402 CAM1 OUT, J403 CAM2 OUT, J404 CAM3 OUT |
R401 |
OW-PASS-RC0402FR-07680RL |
680 | LED series resistor, about 1.8 mA |
R402 |
OW-PASS-0603WAF4700T5E |
470 | SYNC OUT series resistor into the coax, 470 Ω 1/10 W |
R403 |
OW-PASS-0402WGF1000TCE |
100 | InstrumentPort tap on SYNC_OUT, 100 Ω |
U401 |
OW-MISC-SN74LVC1G125DRYR |
SN74LVC1G125DRYR | SYNC OUT driver, ~OE grounded, input SYNC_IN |
U402, U403 |
OW-MISC-USBLC6-2P6 |
USBLC6-2P6 | ESD clamps across the four output jacks (U402 CAM1 with CAM2, U403 CAM3 with SYNC OUT), VBUS on +5V |
| Net | Kind | Pins | Meaning |
|---|---|---|---|
+3.3V |
port | C401.1, U401.6 |
U401's supply |
+5V |
port | U402.5, U403.5 |
the clamps' reference |
CAM1_OUT_BNC |
port | J402.1, U402.1, U402.6 |
camera 1 ExposureActive, 3.3 V behind the block's 470 Ω, to J402 |
CAM2_OUT_BNC |
port | J403.1, U402.3, U402.4 |
camera 2 ExposureActive, 3.3 V behind the block's 470 Ω, to J403 |
CAM3_OUT_BNC |
port | J404.1, U403.1, U403.6 |
camera 3 ExposureActive, 3.3 V behind the block's 470 Ω, to J404 |
GND |
port | C401.2, D401.1, J401.2, J402.2, J403.2, J404.2, U401.1, U401.3, U402.2, U403.2 |
jack shells, the clamps' and the driver's return, the LED cathode |
SYNC_IN |
port | U401.2 |
conditioned Rsync from the inputs sheet, U401's input |
SYNC_OUT_INST |
port | R403.2 |
DIG2: the tap of SYNC_OUT |
SYNC_OUT |
label | R401.1, R402.1, R403.1, U401.4 |
U401's output, the Rsync copy before the 470 Ω; the LED and the tap hang on it |
SYNC_OUT_BNC |
label | J401.1, R402.2, U403.3, U403.4 |
SYNC OUT to the OneBox IO0 at J401 |
| wire | D401.2, R401.2 |
the SYNC OUT LED's anode node |