This question is perhaps better addressed to Microchip tech. support, but I thought there might be someone here that knows the answer through experience, so here goes:
When using the pulsin command on the 08M powered at Vdd=5V, what is the minimum slew rate allowable for logic level signals so that the device can accurately detect high-to-low or low-to-high transitions?
I checked the 12F683 data sheet and did not find anything on this particular parameter. It does state that the inputs are TTL compatible when operating as GPI, and standard logic series data sheets for HC equivalent devices (high speed CMOS) show minimum slew rate = 0.
Of course, there is a timeout of just over 1 minute for this command, so that would set the minimum operational slew rate, but my signals are much, much faster than that. I expect 5 msec. or so transitions, and don't want any nasty surprises if those signals are too slow to detect.
There are some pins with schmitt trigger inputs, but not when operating as GPI. Of course, if that were available here, this issue would be a don't-care....
Additionally, I could turn the pin into an A/D and detect pulses that way, but that takes LOTS more code, so I am trying to stay away from that....
Thanks, Odessa.
When using the pulsin command on the 08M powered at Vdd=5V, what is the minimum slew rate allowable for logic level signals so that the device can accurately detect high-to-low or low-to-high transitions?
I checked the 12F683 data sheet and did not find anything on this particular parameter. It does state that the inputs are TTL compatible when operating as GPI, and standard logic series data sheets for HC equivalent devices (high speed CMOS) show minimum slew rate = 0.
Of course, there is a timeout of just over 1 minute for this command, so that would set the minimum operational slew rate, but my signals are much, much faster than that. I expect 5 msec. or so transitions, and don't want any nasty surprises if those signals are too slow to detect.
There are some pins with schmitt trigger inputs, but not when operating as GPI. Of course, if that were available here, this issue would be a don't-care....
Additionally, I could turn the pin into an A/D and detect pulses that way, but that takes LOTS more code, so I am trying to stay away from that....
Thanks, Odessa.