6802 - RS232

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  hi everyone,
  I am working on a project which has a 6802 processor and standard ram
and eeprom (not decided which bands yet). I wonder If I can write
sofware for 6802 in PC and can send it with rs232 port to eeprom.


Re: 6802 - RS232

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No, you can cross- assemble easily enough on the PC (you won't find a
compiler I don't think), but there's nothing in a 6802 that will let you
load it into memory. You'll need to use an EPROM programmer. The 6802 is
a real antique, unless it's all you can get you'd be better off learning
on a more recent device.

Paul Burke

Re: 6802 - RS232

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 thanks for your information. I have just found out that I need an
eeprom programmer. My mind is clear about this topic. Now I want to ask
you a question. What do you suggest me for using in my project, a PIC
or a microprocessor like mc68000. Which one do you think is better?


Re: 6802 - RS232

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I'd go for one of the more recent single- chip solutions. PICs are
popular and well supported, but very quirky as you'll see if you browse
through some recent threads here. Variants on the 8051 from Phillips and
Atmel have flash and memory on board, and you can get hold of assemblers
easily enough, but you have to pay serious money for a fully- featured C
compiler, though some people have developed successfully with the free
SDCC compiler.

My current choice for little applications is the MSP430 series, for
which good assembler and C tools are available free (mspgcc). The
downside is that they only come in little bitty surface mount packages,
which is bad for the beginner, they don't give you access to the
processor bus, and that they only operate up to 3.6V power supply, which
can make interfacing a bit more difficult. But the upside is that you
can program them serially.

What do you want to do?

Paul Burke



Re: 6802 - RS232
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Neither - the PIC is a horrendous architecture, and is not something to
consider unless the peripherals on the particular device are a perfect
match, while the mc68000 is a dinosaur, and a pain to design around
since it is a pure microprocessor and not a microcontroller (its
descendents, the ColdFire family, are very nice if you need a powerful
microcontroller).

It sounds like you are a complete beginner at embedded programming, and
are taking processor names at random.  You are probably better off
getting ready-made cards with a friendly architectures and decent tools.
  The best choices to look for here are AVR and msp430.

Re: 6802 - RS232
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  Interesting question.  Your choices are a small 8 bit cpu and a 32 bit
one.  Should I drive a scooter or a Car?

You said nothing about your project.  How could anyone guess what you need?


Re: 6802 - RS232
Le Thu, 08 Jun 2006 04:53:55 -0700, ali.keles a écrit :

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http://mcu.st.com/mcu/modules.php?name=Content&pa=showpage&pid70%

For $8.52 you get a nice board with room for connectors.
If you are lucky like I was you could win a dongle.
if not buy the one from Convergence for $59
http://mcu.st.com/mcu/modules.php?name=Content&pa=showpage&pid63%#rlink

Convergence has a free development package (C Compiler and JTAG debugger).
It is limited to 32k code but the debugger is not limited so you could use
assembler or SDCC.

http://sdcc.sourceforge.net/

ST provides free software for their devices on their web site.
You can also get the full data sheets for any parts they sell.

You could still make a nice system with a 6802, 80C31 or Z80 using ST
devices. ST makes devices that have all the glue plus flash and RAM
without a processor. They also have additional ports. I like those
things with a Z80, Z180, HD647180 or HD64180.
SDCC has a Z80 compiler.

GCC for 68HC11 could be easily modified to support the 6802.
The 68HC11 is a modified 6801
ST Software will work nicely with the Convergence JTAG dongle to program
any of their devices.

If it is just a home project a 6802 can still make a nice project with
ST devices and 6821 or 6522 devices. Without an ST device the whole thing
becomes rather expensive unless you have EPROM and RAM and lots of
time on your hands. A design with an ST special device can be of 2 ICs
plus crystal and supply plus resistors and caps while using the standard
design of the days of the 6802 you need at least one ram IC and one ERPROM
plus the chip select glue chip(s). You can get 6821 easily on EBAY. For
the glue chip it can be a PAL, GAL or one to two 74LS138 and some
gates and inverters.

Using http://www.cadsoft.de/ you can draw your circuit. If you use small
devices you could fit all on the maximum free size pcboard.
If not you can still use the drawing part and use a free board program
http://www.devrs.com/e/apps.php
You can then either make your own board or use some service, there are
several low cost options that you can find on the web.

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Re: 6802 - RS232
snipped-for-privacy@gmail.com says...
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So far, I haven't seen the one answer I thought I would.
So here it goes.
     Naturally you can write code on your PC and download it to your
6802 board.  You will need to add a UART to your setup, along with the
associated/proper level shifter.  You will need to write some type of
bootloader program for your board that resides in ROM, it takes the
serial data, usually one of the "standard" file formats (S, hex, so on)
sent one character at a time through the serial port and converts it
into the actual bytes in your EEPROM space.  The bootloader should then
be able to be commanded to execute the downloaded image.
     All in all, it sounds like a pretty good learning experience for
hardware and software.  Anyone here that tells you the 6802 is old news
and then spends the day hacking away at code targeted for a 8051 core is
a hypocrite ;) .
     It is all pretty standard stuff that has been done for ages.  Just
google away on bootloader, motorola S file, and so on, you will have
more info than you could ever dig through.

                                  Jim


Re: 6802 - RS232
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Absolutely correct! I grew up on the 68XX arch back in the 70's and
that 6802 is perfectly capable of doing what you want, and you learn a
bunch in the process of doing it. I think I still have a 6802 board
laying around here somewhere that has an NTSC video interface, an IR
remote input, and some digital outputs to drive analog switches


Re: 6802 - RS232
Le Fri, 09 Jun 2006 14:57:38 -0400, Mike a écrit :

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He was talking about building a board. It can be costly using older
technology. You can learn a lot now with fancy processors at a low
cost. 8051 is more powerfull than 6802. A better approach for someone
who prefers the 6802 would be a 68HC11 which has more support and the
code is similar.
It was good at its days but many processor have come up that are a lot
better since.
A 6802 or Z80 coupled with ST glue chip can make a powerfull system with
little expense unless you have to add special peripherals like serial
chip and USB chips.

For a home hobbyist the best approach though would be the AVR mega
or turbo 8032

http://mcu.st.com/mcu/modules.php?name=Content&pa=showpage&pid70%

Both devices support JTAG debugging and cheap or free development is
easily available.

Stating things like that is not meant to say that designs for 6802
or other devices has no value but that it is hard to underdand why
someone would want to design with old processors when it is easier
and cheaper to design with newer devices.

For Z80 I have made a debugger a few years back and it works well
under dos. I haven't had time to update it to Linux but anyone
wanting to play with it is free to do so.
You might be able to find some debugger for 68xx on the net.

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