| ??? 08/09/06 18:55 Read: times |
#121923 - maybe with TTL, but what about CMOS? Responding to: ???'s previous message |
When we were using TTL, which sinks much more than it sources at its outputs, it was accepted that one would prefer active-low outputs, in general. However, with CMOS, which often sources and sinks more or less equal currents at its outputs, that argument goes away. Further, in the keyboard scanner situation, I don't "see" the difference, i.e. I ask, "where's the advantage of one over the other?" Where would you want to wire-OR rows and columns, and why?
RE |
| Topic | Author | Date |
| High or Low in keypad scanner? | 01/01/70 00:00 | |
| PNP? | 01/01/70 00:00 | |
| maybe with TTL, but what about CMOS? | 01/01/70 00:00 | |
| I would not, the user does | 01/01/70 00:00 | |
| that depends on how you scan the inputs | 01/01/70 00:00 | |
| physical/technological reasons | 01/01/70 00:00 | |
| What sorts of reasons? | 01/01/70 00:00 | |
| early MOS technology | 01/01/70 00:00 | |
| Maybe they did it... | 01/01/70 00:00 | |
| Oxymoron! | 01/01/70 00:00 | |
| you spoilt my joke now | 01/01/70 00:00 | |
| Jokes | 01/01/70 00:00 | |
| We are living in a TTL world... | 01/01/70 00:00 | |
| I don't know why this interests me, but ... | 01/01/70 00:00 | |
| a proverbial answer | 01/01/70 00:00 | |
| So you figure it's just a matter of preference? | 01/01/70 00:00 | |
| You really should get out more! | 01/01/70 00:00 | |
Yes, it's a second childhood ... or maybe a third | 01/01/70 00:00 |