On my first try i ignored that tip, but i knew that i had to fix the power eventually...
In a system where you have the absolute minim of components, it can work even if you ignore that tip a bit. As soon i expanded my system a bit it stopped working. I suspected that that was the issue, so i attached a 470uf capacitor to the eeprom power pins(because of the pin configuration) and it worked once again. Later i had to strip all the thin power wires and put more appropriate wires and make some space for more capacitors(i also added 100uf electrolyte cap near the cpu). Even today i don't have one capacitor for every ic, and it is semi daisy chained, but it works, and i don't plan to fix it, since i am making a new sbc from scrap.

Also when you start building, you must test every step. My first test was the free run test, where i hardwired the cpu data bus to the nop opcode, and i soldered led-s to the address lines, and every led blinked with half frequency of the previous. Next step was adding rom, i soldered led-s to some unused decoded addresses, and the program accessed in a slow loop the addresses of the led-s, by doing that the led-s toggled on and off. Next was ram, i tested it too in a similar way, and after that i added the first i/o device(the VIA chip, 6522).

Thank you, Electric_Eye! Will do!

Is there any way I can view the content of a .rom file? I was wondering if I could build an EEPROM programmer myself. This article inspired me:

http://z80dave.blogspot.co.uk/2011/09/2 ... ammer.html

It seems to me that I just have to send the address and the data/instruction byte then set the WE pin low. It would be fairly easy in Java or Python but I just could not figure out how to view the content of a .rom file. I assume it comprises of a series of address bytes and the corresponding data/instruction bytes. How can I open/view a .rom file in Python/Java? Or is there a way to convert it into text?

How will you interface the EEPROM device to a machine that will be running Python or Java ? Do you want to a Python script to talk to the UART, and send commands to the Arduino board shown in the article ?

Something like that! I might use an atmega 328 with mutlitplexer though, the Mega is just way too expensive for that. But yes, the idea would be to interface the ROM pins with the Arduino digital pins and send the content of the rom file from python/java. I just wonder how can I dissect the rom file to be sent?

The most common type of assembler output file is probably Intel Hex-- either that or Motorola S-record. They're both just text files, so you can view them with any text editor. I have a description of Intel Hex on my website in the large math look-up tables section, at http://wilsonminesco.com/16bitMathTables/IntelHex.html.

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

The 'xxd' program for Linux (or for Cygwin on Windows) will dump a binary file, and can also undump one, which means you can edit the hex as text and convert back to a rom. (I'm assuming a *.rom file is binary, which is to say for an 8k ROM the file will contain 8192 bytes. No formatting or metadata.)

The 'srecord' program (all platforms) will convert between many formats: binary, Intel, Motorola and more.
See http://srecord.sourceforge.net/download.html

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Most things people here will do will have less than 64KB of (E)EPROM space, so they won't be using the type 03 Intel Hex record. I did use it for the large math look-up tables and it was convenient for that because you can manually edit what banks you want the different tables in without changing the individual lines' address fields. I have not used the type 04 which IIRC is for when you go over a megabyte. All three commercial assemblers I've used (including MPASM for the PICs) put out Intel Hex as a default, so that's what I settled into. I don't know if a line starting without a colon could be used for comments like a Mot S0 record. It seems like it could, but I've never tried it.

I've used SRecord 1.60 (for linux) which Ed recommended, to check the validity of files I formed with programs I wrote. It has a ton of abilities to convert EPROM file types and so on. The voluminous .pdf manual could stand to have better command-line examples, but you'll figure it out. Much of the manual is spent on telling about multitudes of file types you will never use, so there's not really that much that you have to read.

Device programmer software will also be able to do file-type conversions, like from Intel Hex to Mot S record to binary, etc..

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Great, thanks!

and I just added some more today about putting discrete components in WW construction, at http://wilsonminesco.com/6502primer/WireWrap.html, about 30% of the way down the page, including pictures of individual pins and a DIP header.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

Thanks. I just added a reminder to that effect.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Garth, your tutorial is probably the best and most exhastive resource about WW. Thsnk you! Just one thing that came to my mind: is it worth to get some alcohol or degreaser to clean the posts?