| ??? 07/03/07 18:54 Read: times |
#141457 - why does it fail Responding to: ???'s previous message |
Richard Erlacher said:
This particular circuit is one of a dozen or more very similar JTAG-capable programmers that I've seen. I've used similar circuits, both home-built and commercially manufactured, that program FPGA's and CPLD's. They've seldom been a problem of any sort. Why are these so difficult to use with ATMEL parts? Is it their (Atmel's) software? Is it the construction technique implemented by home-builders? YES! Plus, this is no JTAG (that's more complicated in protocol, hence slightly more error-resistant). But the AT89S' is SPI-ish. In case of the smallest crosstalk from any signal to clock, or "ringing" on clock, it gives up, or dies fatally rewriting the FLASH, depending on the circumstances. Plus, you have the parasitic supply described oh so many times by Kai, troubles with improper power&reset sequencing (yes, Richard, reset, sounds familiar?) troubles with LPT not being standardised, modern PCs and OSs not liking LPT as a legacy stuff and doing funny things with it, problems with timing in modern OS... Chose your favourite. JW |
| Topic | Author | Date |
| AT89 ISP | 01/01/70 00:00 | |
| alternative | 01/01/70 00:00 | |
| I found this in this forum | 01/01/70 00:00 | |
your link was helpful! | 01/01/70 00:00 | |
| Why do so many people "search" rather than "use" | 01/01/70 00:00 | |
| why does it fail | 01/01/70 00:00 | |
| So it's ATMEL's fault? | 01/01/70 00:00 | |
| it\'s not just Atmel | 01/01/70 00:00 | |
| Thank you.. | 01/01/70 00:00 | |
| few details required | 01/01/70 00:00 | |
| Either build and use what they recommend, or quit! | 01/01/70 00:00 | |
| and .. | 01/01/70 00:00 | |
| There\'s been a lot of discussion about this ... | 01/01/70 00:00 | |
| also | 01/01/70 00:00 | |
| Ok. Thank you. | 01/01/70 00:00 |