Pic's pin DC impedances

[yves-michel]

Hello All,

I use a lot of Microchip Pics for my simulations. I was wondering if the pics pins on the simulation respect their respective impedances, particularly for DC voltages not worry about the pin capacitance.


Regards,

Yves

[Ettore]

The PICs models in Proteus must interact with other simulated components of the schematic, therefore an interface mechanism - called Interface Model - had to be devised. Such of particular mechanism creates for any input/output pin an ADC/DAC interface by setting voltage thresholds or levels, hysteresis, general timings and dc resistances. The dc resistances in particular are defined for PICs as:

Resistance for strong digital levels - RSHI, RSLO = 20 Ohms
Resistance for weak digital level - RWHI = 20k
Output resistance for floating condition - RTS = 100M (default) or 10G when the PIC supports the "Capacitive Sensing Module" (CSM)

Those values are defined into the interface model file ITFMOD.MDF, in the installation directory MODELS.

Note that interface model values won't change due to clock frequency, temperature or other environmental conditions like the part in the real world. This is because the PICs simulation is substantially a simple programming digital model where the user's code and any effects on internal (supported) peripherals are emulated at the max speed and efficiency possible. This means that PICs models emulate not at all or just partially many physical aspects of the real part.

[yves-michel]

Ettore,

Many thanks for your explanation.

Best regards,

Yves