| ??? 12/25/05 23:44 Read: times |
#105944 - Another note Responding to: ???'s previous message |
Perhaps noteworthy is the following e-mail I received on Dec. 20, 2005. I have not yet evaluated it in the context of ISP, but I'll pass it along here for your consideration.
To: dhenry@sprynet.com
Subject: Programmer, adding schottky diodes?
Sender: frieder.ferlemann@...
Hi Dan,
I just looked at your project page at 8052.com and
fear that the level conversion circuit might
violate the device's input ratings:
PC AT89S'
DTR>----/\/\/\----+--->MOSI
10K |
|__|__
Clip DTR ^ | 5.1V
to 0-5V /_\ Zener
|
|
GND
I'd suggest to add a Schottky Diode in parallel to
the Zener Diode in order to better limit the negative
voltage?
Otherwise the internal diodes of the AT89Sxx might
be used to clip the voltage (not really dramatic
but not nice either:)
Greetings,
Frieder |
| Topic | Author | Date |
| serial port ISP programmer | 01/01/70 00:00 | |
| Links | 01/01/70 00:00 | |
| ponyprog | 01/01/70 00:00 | |
| no luck yet | 01/01/70 00:00 | |
| it will be cheaper to bou an USB paralle | 01/01/70 00:00 | |
| USB Parallel Ports | 01/01/70 00:00 | |
| solutions | 01/01/70 00:00 | |
| Doesn't work | 01/01/70 00:00 | |
| it works only for the AT89S8252 | 01/01/70 00:00 | |
| Are you certain it's a software problem? | 01/01/70 00:00 | |
| i have tested the hardware | 01/01/70 00:00 | |
| Test the hardware with the application | 01/01/70 00:00 | |
| I did test it | 01/01/70 00:00 | |
| Only TX? There are 3 more to test. | 01/01/70 00:00 | |
Another note | 01/01/70 00:00 |