A registered peripheral model runs in the engine: the firmware talks to it over the real bus and gets device-accurate responses.
Quad 1-of-2 FET bus switch (core/configs/devices/74cbtlv3257.yaml), 1 ns. ⚠️ A FET SWITCH IS NOT A BUFFER: on silicon it is four pass transistors and bidirectional through the closed path; modelled here as a one-way mux, because two pads cannot become one net. A design that drives Y and reads it back on the selected input side will not see its own data.
Simulated device model
Built from the datasheet. Implemented from the part’s register documentation and exercised by automated tests. Nothing physical was ever placed next to it.
GPIO_GROUP
[object Object]
| Pin | Type | Role |
|---|---|---|
A1 | input | — |
B1 | input | — |
Y1 | tri_state | — |
A2 | input | — |
B2 | input | — |
Y2 | tri_state | — |
A3 | input | — |
B3 | input | — |
Y3 | tri_state | — |
A4 | input | — |
B4 | input | — |
Y4 | tri_state | — |
S | input | — |
OE | input | — |
VCC | power_in | — |
GND | power_in | — |
Modelled from Texas Instruments SN74CBTLV3257 datasheet.