Processor begins...? - Page 2 - Electronic Circuits Projects Diagrams Free

ArtemisGoldfish · 23rd March 2007, 04:11 PM

Quote:

Originally Posted by 3v0

Not a problem. I am an old Z80 fan.

At one time a friend and I built a SBC Z80 that ran forth. It used 2 SCC chips (4 serial channels), other then that most 16F pics would run rings around it.

I'm rather interested because at a Salvation Army (Goodwill-type store) a year or so ago when I was starting with electronics, I found a Z80 kit with all it's IC's, only missing a few resistors, but I had lots. Unfortunately, I accidentally killed the board with my 25-watt iron (Darn glass-epoxy boards and fragile leads), but I'm interested in building a simple computer now that I know some of the theory. The board I found at Salvo was a 4-chip setup: CPU, RAM, ROM, and Logic.

kchriste · 24th March 2007, 03:37 AM

Quote:

I'm interested in building a simple computer now that I know some of the theory.

Your biggest problem will be getting a ROM programmed with the proper boot code so you can load code into RAM/EEPROM and execute it. There are ROM emulators out there that are ideal for experimenting with building your own simple computer board:
http://elm-chan.org/works/erom/report_e.html

**3v0** · 24th March 2007, 11:52 AM

Nigel:
I agree.

At some point I recall seeing some Microchip with a memory bus (interface). IIRC it was a surface mount part with lots of pins.

ArtemisGoldfish:
This project is not a simple one.
Are you sure you can not fix the kit you have?
It may be worth finishing for historical reasons depending on what it is.

After you get the basic computer working you may want to look into some of the Zilog Periferal chips like the CTC as SCC. Both were powerful chips in their day.

In regard to kchriste's post. The link is for a ROM emulator with a ROM MONITOR loaded. It would be handy to have.

Sceadwian · 24th March 2007, 06:27 PM

I have an AVR chip that has an external memory bus interface and it's in DIP, microchip must have at least one?

**Nigel Goodwin** · 24th March 2007, 08:38 PM

Quote:

Originally Posted by Sceadwian

I have an AVR chip that has an external memory bus interface and it's in DIP, microchip must have at least one?

They certainly have in the past, if I recall correctly you could configure the pins as either external memory or I/O - no idea if they still make one?, or even what it might have been called?.

Papabravo · 24th March 2007, 11:01 PM

Quote:

Originally Posted by Nigel Goodwin

They certainly have in the past, if I recall correctly you could configure the pins as either external memory or I/O - no idea if they still make one?, or even what it might have been called?.

17C42
http://ww1.microchip.com/downloads/e...Doc/30412c.pdf
Looks like external program memory - not sure about RAM/IO memory

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24th March 2007, 11:52 AM	(permalink)
3v0	Nigel: I agree. At some point I recall seeing some Microchip with a memory bus (interface). IIRC it was a surface mount part with lots of pins. ArtemisGoldfish: This project is not a simple one. Are you sure you can not fix the kit you have? It may be worth finishing for historical reasons depending on what it is. After you get the basic computer working you may want to look into some of the Zilog Periferal chips like the CTC as SCC. Both were powerful chips in their day. In regard to kchriste's post. The link is for a ROM emulator with a ROM MONITOR loaded. It would be handy to have. Last edited by 3v0; 24th March 2007 at 12:01 PM.

24th March 2007, 06:27 PM	(permalink)
Sceadwian	I have an AVR chip that has an external memory bus interface and it's in DIP, microchip must have at least one? __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har."