| ??? 08/23/08 14:51 Read: times |
#157693 - Keep your work clean and wires short Responding to: ???'s previous message |
Muthuswamy Dikshit said:
@Jon Thanks for the link, i got the ISP cable schematics there. I think it is for CPLD. I don't know if its OK for 89S51. I have not yet made it. I will try. One doubt-Is the Error detection module mandatory? @Richard "If you just blindly take someone else's circuit and attempt" >>did not blindly take it up. We made own code also. As it din't work I tried other circuits. What I meant by blindly was without any further knowledge of the details of the circuit, e.g. why this component, and not that one. "The use of a solderless breadboard is often a fatal mistake."
>> I'm learning soldering. I used bread board to check if the set up works. If it "works" on a solderless breadboard, it may, in fact, work, but there's no guarantee. It may only appear to work. "It may work on one day, after much effort, and not at all the next." "They really aren't suitable for electronics operating at much higher frequency than about speech-level audio."
>>Yes, I agree but the clock period i used was 2s! If I see it working I will definitely make a PCB. I wouldn't be in such a hurry. Take your time and be sure everything is correct, and not on a solderless breadboard, before expending resources on a PCB. Do you have some practical frequency upper-limit for bread boards? I don't consider anything above ~3 kHz unconditionally valid on a solderless breadboard. Even DC circuit behaviors can be distorted by the solderless breadboard. I neatly fixed the micro onto the breadboard and fixed a 4Mhz(with the two capacitors) crystal across pin 18 and 19 on the breadboard itself. Is this really OK? Well, the hookup may be correct in the sense that it's the way it should be connected. However, solderless breadboards introduce (according to the specifications for the ones I have, and seldom use) about 5 pf of contact-to-contact capacitance, and provide absolutely minimal power distribution of the lowest conceivable quality. They have high contact resistance and high stray capacitance. You have very little control at the outset, and can conclude very litte after the completion of a circuit. Soldering should take no more than 15 minutes to learn, aside from simple "clean" work habits. If you get a good-quality fine-tipped soldering iron, good-quality solder, and proper (whatever that means) flux, and keep your surfaces clean, you should have no trouble. Wire-wrap or point-to-point soldering is a much better and safer (from the standpoint of circuit integrity) way to build digital circuits. Some people have problems with wire-wrap as a technology for high-impedance, high-gain analog circuits. I do prefer point-to-point soldering for high-frequency (>2 MHz) analog circuitsm though I've wire-wrapped some analog circuits up to 10 MHz. RE |
