Newbie question..Schematics request

[jagzviruz]

Hello all people .. First post ..

I am completely new to automation .. So i dont know anything .. I have fiddled around in manual conmtrolled till now ..Now I have a bit of knowledge on the 8085 MC and a few other micro controllers .. theory only ..

I was told that in order to use them MC in making automatd bots like Micromouse etc .. we need to program the chip thru a PC's parallel port and then run the program ..

My question is an anyone guide me with making this circuit that programs a Chip via Parallel port ..schematics would be a lot help .. yeah i have a pretty sound knowledge in using and writing code in assemble .. but not in practicals .. I have used the standard LAB kits only .. I want to make a automated one .. so anyone's help will be highly appreciated ..

In addition i also wanted to know about the PIC and the related schematics ..

 

[dknguyen]

You mean that you want to learn how to implement a microcontroller onto a PCB? It's pretty simple (unless you get the high end chips, but those tend to be called processors). You will need to know some electronics. You basically have a voltage regulator that regulates the power going to the uC's power supply pins, and an oscillator circuit/crystal going going to the uC's clock pins. That's pretty much it. You just run out your I/O pins to whatever device or interface circuitry you need.

Normally, for the software what you do is you get a compiler for the chip (and usually but not always, the compiler has the ability to upload the code to your chip too).

If the chip has in-circuit programming (ISCP) capability, you get a ICSP programmer device where one end goes to the PC and the other end goes to a some special pins that you have run out to a plug on the PCB. THe software and the programmer will upload the code.

The programmer usually plugs to the PC through a serial cable (not parallel port, takes too many pins and is clunky). Even that is getting replaced by USB now...

THere is also the external programmer where you use a socket for the uC on the PCB and you remove the uC from the socket and stick it into a socket on the programmer to upload code. THen you stick it back into the PCB socket.

 

[Nigel Goodwin]

The programmer usually plugs to the PC through a serial cable (not parallel port, takes too many pins and is clunky). Even that is getting replaced by USB now...

Actually, the parallel port was by far the most popular port used for PIC's, although now it's probably been over taken by 'true' serial port programmers and USB programmers.

The parallel port isn't 'clunky', and it doesn't take too many pins, it takes exactly the same as the 'false' serial port programmers.

There are basically THREE types of PIC programmers in common use:

1) Parallel port - from the 'father of PIC programmers' David Tait, uses a few of the port pins to create the required syncronous bi-directional serial interface.

2) 'Serial' port ones (that I called 'false' above), doesn't actually use the serial port at all, it uses the handshake lines to create the required syncronous bi-directional serial interface - just like the parallel port. These are generally the most unreliable and troublesome programmers! - essentially because you can 'cheat' and make a VERY low component count programmer, IF your serial port is above the RS232 spec.

3) Serial and USB programmers - these have a processor on board, this does the actual programming. The connection to the computer is simply to transfer the data to the processor, these are the most expensive programmers - as they are by far the most complicated.

All official MicroChip programmers are type 3, so are fairly expensive. Luckily they make the firmware available (so you can upgrade them), so a popular project is an ICD2 clone, a programmer and debugger.

 

[jagzviruz]

Unsatisfied yet

Hi ..

PLeasant to have the senior members answering . I could understand what you have said to me in both your posts .. ut i still dont know how to make the circuit which is used to uload the code to the chip .. from the serial port .. I was asking for that circuit in whose socket when the MC is placed and conneted to the port , the compiler can upload the code ..

Hope to hear soon ..

 

[philba]

what you are referring to is a programmer. However, I didn't see which microcontroller you want to use. A lot depends on the chips you will be using. If it's the 8085 you mentioned, then you have a lot of work to do and I would suggest you rethink that choice. PICs? AVRs? Z8s? 8051/52? MSP430? MaxQ? Something else? It's a big universe out there...

You'll have to give more info if you want people answer your questions.

By the way, the reason that people view the parallel port as clunky is that newer versions of windows (2K and later) make it hard to use. Once you get it working, it's rather fast. None of that os overhead getting in the way...

 

[Nigel Goodwin]

Hi ..

PLeasant to have the senior members answering . I could understand what you have said to me in both your posts .. ut i still dont know how to make the circuit which is used to uload the code to the chip .. from the serial port .. I was asking for that circuit in whose socket when the MC is placed and conneted to the port , the compiler can upload the code ..

For what type of processor?. Certainly for PIC's there are a great many choices, which are easily found via google. My website contains a number of parallel port designs - I don't consider serial port ones (at least 'false' serial port ones) reliable enough to support, which is why WinPicProg doesn't support them.

 

[eblc1388]

.. I was asking for that circuit in whose socket when the MC is placed and conneted to the port , the compiler can upload the code ..

That is a hardware programmer and versions exist for either the PIC and AVR microcontroller families. Programmers are not interchangeable between uC famiulies of different manufacturers.

The parallel port programmer for AVR is the simplest and mostly trouble free for beginners to build as no power supply is involved. Also two versions are available from as simple as several resistors to one using a single 74HC244. Once built, user can download the compiled/assembled code into the AVR.

The parallel port programmer for PIC is a little bit more involved as it will need to switch two different voltages(+5V and +13V) in order to properly program a PIC. Many things can go wrong for a beginner and he or she often has no clues as to where the problem is. So in this aspect, the AVR parallel port programmer is much simpler and has a near 100% success rate. Here is the link for one:



But don't let this tempt you into choosing AVR over PIC immediately. If you are a beginner and have not decided to choose between learning PIC or AVR, I would suggest you try the PIC first. The schematic of the parallel port programmer P16PRO40 can be found in the links beneath Nigel's signature.

Edited: correct bad spelling.

 

[jagzviruz]

Thankful

Big Thanks to all the senior members .. who helped me ..

Sory about the delay but i had a problem with access.. .By the way .. what are the different pros and cons of using avr and pics ??

does the atmel 8051 have features unique to itself ?