??? 02/02/12 02:26 Read: times |
#185770 - Please explain what the "power-on glitch" is ... Responding to: ???'s previous message |
First of all, I have to agree with Michael, that you're just inventing excuses for (a) your failure to read and understand the datasheet, and (b) for your apparently complete ignorance of industry practice in this field.
I've been doing things with digital logic, microprocessors, microcontrollers, etc, since the '60's, and used the original 8051 back when it was just a pup, not to mention its predecessors. Every one of these chips starting with the 8048 had much stronger negative-going drive than positive, and that, quite simply, was because of industry convention. Drivers back in the day, were always inverting open-collectors, until considerably later when tristate drivers, which, BTW, were still active-low types, became common. Even those were mostly inverting types, since, back then, one communicated with other devices over a bus, which, then, was often a backplane which, in turn, required receivers on the target boards. Low-side high-current drivers were driven with a positive output only to provide low-going drive to relays, LED cathodes, etc. Current was most commonly limited by resistors at the high-side, and the driver sank the current. As target devices became less power-hungry, the MCU's themselves became capable of driving some of them, hence, relatively high-current-sink low-current-source drivers at the MCU pins. If you really believe that the PIC-series is a better choice for you, I'd encourage you to use it. I wouldn't waste another moment worrying about the things you don't like in the 805x series. Having, myself, spent many, Many, MANY hours with oscilloscopes and logic analyzer on various 805x's, I'd be really interested in details about what it is to which you refer as that "power-on-glitch." I'd bet there's another term for it. RE |