| ??? 04/04/08 00:04 Read: times |
#152941 - no scope Responding to: ???'s previous message |
My circuit is just to fulfil the loader reset mode and controls the EA, RST and PSEN lines, controlled by DTR. I'm using a 74HC245 tristate buffer for this which seems to be ok according to the Dallas datasheet.
My oscillator is currently a 15MHz crystal and two 27pF. It must oscillate but I suppose it could be unstable. I tried several crystals and this one seemed to work best. I tried two PSUs and two computers with different software. I have no scope to check the PSU lines. I'll have to think where I could get one. When my second chip comes, I'll try that. If the same thing happens, then I'll start to worry about my sanity. |
| Topic | Author | Date |
| Take this up with the Maxim/Dallas support guys | 01/01/70 00:00 | |
| Why ? | 01/01/70 00:00 | |
| meaty PSU | 01/01/70 00:00 | |
| Mke sure you've got the right software | 01/01/70 00:00 | |
| Dallas MTK | 01/01/70 00:00 | |
| You've got to use exactly the parts they recommend | 01/01/70 00:00 | |
| no scope | 01/01/70 00:00 | |
| I'm not sure this is a deal-breaker ... | 01/01/70 00:00 | |
| same with DS89C420 | 01/01/70 00:00 | |
| decoupling | 01/01/70 00:00 | |
| I have no confidence at all in "breadboards" | 01/01/70 00:00 | |
| stripboard circuit works! | 01/01/70 00:00 | |
| about that bootloader ... | 01/01/70 00:00 | |
| that will not help | 01/01/70 00:00 | |
about those decoupling capacitors | 01/01/70 00:00 | |
| In case you're curious ... | 01/01/70 00:00 | |
| my DS89C450 experience was... | 01/01/70 00:00 | |
| What did you do? | 01/01/70 00:00 | |
| 8052.com SBC | 01/01/70 00:00 | |
| How considerate! | 01/01/70 00:00 | |
| progress ? | 01/01/70 00:00 | |
| programming circuit variations ... FIY | 01/01/70 00:00 | |
| DS89C430 boot loader | 01/01/70 00:00 |