| ??? 03/11/07 18:44 Read: times |
#134718 - hmm Responding to: ???'s previous message |
after further testing, I'm starting to discover that my 8051 system itself isn't working properly.
In a typical setup, if all address/data lines were tied low through resistors (mine are like that and the resistors are 10K) and the system was running, I would think that the system would increment the program counter constantly, because the only instruction processed at each location is a NOP (instruction #0). I'm thinking that maybe 10K resistance is too high to make the 80C51BH processor think that it is defaulted to low, but I don't want to heat the chip. Right now, if I remove the EEPROM and only have the 80C51-BH in place, a binary count must occur at the speed of the clock. right now I have it at 8.064Mhz. It seems now that A0 through A7 are high. when I went through each address line I didn't see a constant transistion from high-low-high. Either one stayed high or stayed low. My capacitors next to the crystal are 33pF each. The crystal appears to be running according to further tests, and the reset is low. |
| Topic | Author | Date |
| 8051 board somewhat working | 01/01/70 00:00 | |
| Give us a clue then.How does it partialy work?? | 01/01/70 00:00 | |
| HC AC ???? | 01/01/70 00:00 | |
| you will most likely need pullups | 01/01/70 00:00 | |
| pull ups | 01/01/70 00:00 | |
| be more specific | 01/01/70 00:00 | |
| interesting tests | 01/01/70 00:00 | |
| interesting they may be, but | 01/01/70 00:00 | |
| to verify | 01/01/70 00:00 | |
| interesting they may be, | 01/01/70 00:00 | |
| Checksum? CRC? | 01/01/70 00:00 | |
| hmm | 01/01/70 00:00 | |
| You probably need an oscilloscope | 01/01/70 00:00 | |
| sorry for asking | 01/01/70 00:00 | |
| not the first... (or last :-) | 01/01/70 00:00 | |
| Maybe my naging helped ... | 01/01/70 00:00 | |
| why EPP? | 01/01/70 00:00 | |
| why epp can be faster | 01/01/70 00:00 | |
| Epp requires a bit less logic and is WAY faster | 01/01/70 00:00 | |
| about that schematic ... | 01/01/70 00:00 | |
| a matter of taste | 01/01/70 00:00 | |
| I have to agree ... | 01/01/70 00:00 | |
you may not have discovered this | 01/01/70 00:00 | |
| you have to investigate | 01/01/70 00:00 | |
| indeed | 01/01/70 00:00 | |
| Amazed! | 01/01/70 00:00 | |
| What? | 01/01/70 00:00 |