isp flash programmer for 8051

hey, i found a programmer schematics at here.
i made it but i faced some problem programming with it.
When i 1st try it, it is able to read, write and verify but many a times "there is no response from uC" is displayed. After some times, there's completely nothing working out. Every time when i try to do operation to the uC it says " there's no response from uC". I try changing the uC but result still the same. i guess the buffer is ok because when i open a hex file, buffer will be filled with hex codes.... I checked the circuit over and over again but still i cannot find a way to solve this.... Please help me.......

Hi, cruellays

i guess the buffer is ok because when i open a hex file, buffer will be filled with hex codes.

Which Buffer are you checking ?

there's a tristate Buffer IC 74HCT541 between LPT port and micro, check if its OK
and the Buffer you are talking is the Hex Buffer window in the ISP S/W prog.

in the past i tried the same ISP programmer with Buffer IC and w/o buffer IC both worked few times and later stopped working ( typical Problem with these DIY type programmers), Finally i got a Professional universal programmer and when i checked the AT89S52 chip ( that i tried on ISP prog) the Chip was damaged/spoiled by the ISP prog. it could not be programmed even by the Parallel High Voltage Professional Programmer, so i had to discard a new unused 89S52.

My advice would be to stop wasting time and pulling hair :mad with these DIY ISP prgmrs, they cannot guarantee success each time. there's also a danger of damaging your LPT port ( or even your Mother Board). So buy a Professional Programmer if you are planning a long time career in embedded design.

with DIY prgrms you'll be spending more time in trying to make the prgmr work and less time in writing your code



Arun

Yup, i totally agree with Arun, these do-it-yourself programmers are not always successful, and there designers/authors do not offer support.

i tried mailing to designer of ISPpgm (Mr.Asim Khan) but his mail id is invalid/non existent.

@nischay,
that is not always true. It deends upon the circuit and how u have chosen to assemble it.
i have been using ISP DIY programmers for a long time right from the time i used 89sXX series and am succesfully using another one too to program AVRs.
let us say it is just like a virus attack on ur PC.If u are careful enough , such things like accidents don't tend to happen .
As for the commercial programmers, the good ones come at astronomical prices (not particularly affordable for most of the students) and the cheaper ones have the same risk factors as the DIY ones.
:-)

@nischay,
that is not always true. It deends upon the circuit and how u have chosen to assemble it.
i have been using ISP DIY programmers for a long time right from the time i used 89sXX series and am succesfully using another one too to program AVRs.
let us say it is just like a virus attack on ur PC.If u are careful enough , such things like accidents don't tend to happen .
As for the commercial programmers, the good ones come at astronomical prices (not particularly affordable for most of the students) and the cheaper ones have the same risk factors as the DIY ones.
:-)

pdi33

Can I have ur programmer's schematics? I cannot find any thing wrong with the hardware of the one i'm doing now.

@cruellay,
u can try the SI prog/STK200 programmer hardware for the same software

btw, have u shorted pin 2 and 12 of the DB25 connector?

I successfully built this one, I used Mr. Asim software too (ISP-3v0) .
http://www.kmitl.ac.th/~kswichit/ISP-Pgm3v0/ISP-Pgm3v0.html
Run the ISP-XP.bat for Windows XP. The parallel port cable connections needs to be rewired too.

The conditions are : I only used AT89S51 and I never lock any bits.

O.O
I had shorted the pin2 and pin12 of the DB25 connector... pin 18 is to ground according the the schematics, but i shorted pin 18 until pin25 all to ground. I hope i'm not doing that wrong..

Freddy, what u mean is we do not need 74hgt541 and straight connect to the 8051 as shown in schematics?

well cruellays,
a buffer in between is always safe . It protecs the LPT port from the power supply transients of the target board and vice versa.