| ??? 02/09/05 14:49 Modified: 02/09/05 14:50 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#86987 - talking about memory Responding to: ???'s previous message |
It only adds you noise immunity at the cost of increased supply current. And sometimes I like to play on the safe side. That's all.
1) Port pins should never leave the board, I would NEVER do 2) 2) If the port pins leave the board, pullups is a great idea. 3) If the port signals leave the board buffers should be used 4) if the port pins (except P0) do not leave the board, pullups are not needed. 5) If you skimp on PCB (no ground plane) 4) may be invalid. ad 5) One of the great things about this forum is that you get all perspectives. In a professional environment (always ground planes etc.) 5) never comes up because a proper designed board does not have such noise immunity issues. In an "economical" environment (1 or 2 layer PCB) pullups may very well be required due to the noise suspectability of such a board. I freely admit that when Jan see such a point and bring it up my first reaction is HUH? because I do not think of issues with "econoboards". I got to 4) before I realized the possible implication on an "econoboard" So, please do not see this as a "fight" or difference of opinion, it is a difference of perspective. Erik |
| Topic | Author | Date |
| P2:R0 as memory pointer | 01/01/70 00:00 | |
| Read the cpu data! | 01/01/70 00:00 | |
| P2 readback | 01/01/70 00:00 | |
| Re | 01/01/70 00:00 | |
| Thank you all | 01/01/70 00:00 | |
| Interesting | 01/01/70 00:00 | |
| very well described | 01/01/70 00:00 | |
| This is NOT in the | 01/01/70 00:00 | |
| ch3 pg 6 | 01/01/70 00:00 | |
| none of them | 01/01/70 00:00 | |
| more | 01/01/70 00:00 | |
| An experiment - AT89C8252 | 01/01/70 00:00 | |
| not necessarily | 01/01/70 00:00 | |
| sure not necessarily | 01/01/70 00:00 | |
| talking about memory | 01/01/70 00:00 | |
| MOVX multiplexed with P2 SFR data | 01/01/70 00:00 | |
| Now I say: HUH | 01/01/70 00:00 | |
| huh | 01/01/70 00:00 | |
| Thank you | 01/01/70 00:00 | |
| what datasheet says | 01/01/70 00:00 | |
| I should've RTFM... :-) | 01/01/70 00:00 | |
| not too much logic | 01/01/70 00:00 | |
| sure | 01/01/70 00:00 | |
| The horses mouth | 01/01/70 00:00 | |
| horse is plural | 01/01/70 00:00 | |
| I'd be happy to ... | 01/01/70 00:00 | |
| can't find them | 01/01/70 00:00 | |
As you use to say :) | 01/01/70 00:00 | |
| another note | 01/01/70 00:00 |