| ??? 12/30/05 23:32 Read: times |
#106248 - ds89c420 programmer |
I saw a number of pages about the 89c420 programmer in posts about 12 months ago, people were talking about how easy this programmer was to build.
However, in looking at the schematic, I'm having a hard time with the connection with the ac/hc125 and the uP. It see that DTR latches the Vcc sending the RST pin high and that DTR also sets the EA\ low. But there is a connection with the second set of 125 ports that I don't understand, specifically where is the '4th' port of the first gate? If this isn't clear, I'll try to clarify it. TIA |
| Topic | Author | Date |
| ds89c420 programmer | 01/01/70 00:00 | |
| clarification | 01/01/70 00:00 | |
| schematic | 01/01/70 00:00 | |
| Now I understand what you mean... | 01/01/70 00:00 | |
| so, I'm correct? | 01/01/70 00:00 | |
| Yes, you are | 01/01/70 00:00 | |
| not to beat a dead horse | 01/01/70 00:00 | |
| Much more | 01/01/70 00:00 | |
| given | 01/01/70 00:00 | |
thanks | 01/01/70 00:00 | |
| DS89C420 ISP | 01/01/70 00:00 | |
| isp response | 01/01/70 00:00 | |
| External access | 01/01/70 00:00 | |
| caps for crystal | 01/01/70 00:00 | |
| Only NP0 ceramics! | 01/01/70 00:00 | |
| over my head | 01/01/70 00:00 | |
| NP0, X7R, Z5U | 01/01/70 00:00 | |
| digikey will be my friend | 01/01/70 00:00 | |
| Everybody probably already knows | 01/01/70 00:00 | |
| Overlapping standards | 01/01/70 00:00 | |
| holy moly | 01/01/70 00:00 | |
| Oh dear...! | 01/01/70 00:00 | |
| now you're playing me right? | 01/01/70 00:00 | |
| Not really | 01/01/70 00:00 | |
| yes really ;) | 01/01/70 00:00 | |
| one more thing | 01/01/70 00:00 | |
| Sure | 01/01/70 00:00 | |
| max232 charge caps | 01/01/70 00:00 | |
| Yes | 01/01/70 00:00 | |
| a good reference for this . . . | 01/01/70 00:00 | |
| thx | 01/01/70 00:00 |