| ??? 11/11/05 14:28 Modified: 11/11/05 14:34 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#103574 - You could try this... Responding to: ???'s previous message |
Roberto said:
I know that this is the right part to build it but what I mean is that for instance in Venezuela none supplier sells this part, I do not know about other countries. Then what can we do? Design any solution to build the cable, maybe with other parts, buffers etc, but that can be build with parts around us. Refering to the circuit in http://www.atmel.com/dyn/resou...p_C_v5.PDF you can try the following buffer/line driver module: 
Apply Vbuffer (5V) to the unconnected programmer. Then, start the atmel's ISP software, plug the programmer into the printer port, connect the programmer cable to the target, turn-on the target's Vcc (5V) and do the progamming. After the programming is finished, turn-off the target's supply voltage, then remove the programmer cable from the target. Disconnect the programmer from the printer port and turn-off Vbuffer. Some hints: Vbuffer and Vcc aren't the same, of course! Choose an independent 5V source for the buffer. Connect a 4k7 pull-up resistor directly at reset pin of AT89S52. Take care that input voltage at 74HC244 is within regular input voltage range. Means, input low voltage, which is the sum of output low voltage of 74HCT244 (<0.1V) and voltage drop across Schottky diode (0.3V), must not be higher than 0.4V! The 74HCT244 cannot be omitted, because otherwise the diode resistor network will not produce regular signals! This comes from the fact, that printer port signals are mostly no 5V-CMOS signals, but TTL. Kai |
| Topic | Author | Date |
| atmel isp | 01/01/70 00:00 | |
| check out | 01/01/70 00:00 | |
| isp | 01/01/70 00:00 | |
| home Atmel ISP cable | 01/01/70 00:00 | |
You could try this... | 01/01/70 00:00 | |
| VHC-version is needed | 01/01/70 00:00 | |
| absolutely necessary? | 01/01/70 00:00 | |
| If it was so simple... | 01/01/70 00:00 | |
| 74vhc244 | 01/01/70 00:00 | |
| No access to digikey in Australia? | 01/01/70 00:00 | |
| can somebody please explain | 01/01/70 00:00 | |
| Here comes my explaination | 01/01/70 00:00 | |
| bad nomenclature ... | 01/01/70 00:00 | |
| Nomenclatura | 01/01/70 00:00 | |
| just explaination | 01/01/70 00:00 |