| ??? 02/11/05 19:48 Read: times |
#87173 - The horses mouth Responding to: ???'s previous message |
Bill Houghton said:
We went and looked at the port logic schematics for one of the 80C51 family derivatives this morning. When P2 is driven with the high byte of the address the strong pullup will be on for 2 clocks. When switching back to the P2 SFR data, the strong pullup will be on if the address info was a zero and the P2 SFR data is a one.
I can't say about other mfgrs, but this is the case for Philips devices. Has anyone ever posted here before who is quite this close to the real hardware ? Thanks Bill Steve |
| 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 |