EASy68K  
It is currently Tue Apr 25, 2017 6:27 pm

All times are UTC




Post new topic Reply to topic  [ 6 posts ] 
Author Message
PostPosted: Wed Apr 05, 2006 5:46 pm 
Check out item number: 7606301125 Buy It Now

I bought one a few weeks ago, and have had a chance to play. They are identical (as far as I can tell) to the original MECB board, apart from:

1. No tape interface - I'm working on a PCB to do this.
2. ROM is in a different location and larger.
3. More RAM.

There is a problem with the shipped ROM - the version of Tutor 1.3 installed does not handle TRAP #14 commands. I tracked this down to an assembly error (macro handling) causing the TRAP #14 vector table to have incorrect entries (the entries are supposed to be COMMAND << 24 + jump offset but are COMMAND << 16 + jump offset thus corrupting the address).

I have downloaded the version of Tutor 1.3 for Easy68k and assembled it. So far it works when located in RAM, I am waiting for some 27C512 and an EPROM burner to burn some updated ROMs. I see no reason why these shouldn't work.

Once that's done I'm going to write a TRAP #15 handler compatible (for the most part) with Easy68K. Then it will be a simulator with a purpose :D

I'm also investigating when I can 'recreate' the hardware window of Easy68k in reality :wink: I'll let you know how I get on.

Discussion of any of these topics is most welcome. I have rediscovered 68k and 'hard' programming, digital logic design and schematic/PCB design and am secretly loving it!

ps - there is no ethernet on this board - two serial ports and a parallel printer interface (with an additional two 8-bit I/O ports) - see MECB doco, facilities are the same (with exception of tape interface as detailed above).

Mark.


Top
  
 
 Post subject:
PostPosted: Thu Apr 06, 2006 3:08 pm 
Offline
User avatar

Joined: Thu Dec 16, 2004 6:42 pm
Posts: 1036
Location: Monroe County Community College, Monroe Michigan, U.S.A.
Sounds like a fun project.

I have an MECB connected to the serial port of my Linux server which in turn is connected via SFTP to the Internet. I can log on to the Linux server from anywhere and then access the MECB :D

_________________
Prof. Kelly


Top
 Profile  
 
PostPosted: Fri Apr 07, 2006 4:28 am 
Offline

Joined: Mon Dec 27, 2004 11:40 pm
Posts: 318
murkles wrote:
Once that's done I'm going to write a TRAP #15 handler compatible (for the most part) with Easy68K. Then it will be a simulator with a purpose :D

I've done that. I'm finishing the disassembler that displays the next code line when tracing code.

The whole thing is a portable BIOS that supports EASy68K s-records, most of the TRAP #15 calls for text I/O or time functions and an EASy68K like register display.

Also included is EhBASIC, with command line options that support any memory size and warm restarts after a hardware reset or an EXIT command.

Still to do is breakpoint handling and tidying up of details of the user interface which is serial based.

The requirements are, at the moment, 24K of ROM, 8K of RAM, serial I/O and a timer, though if you don't need the time fumctions the timer can be omitted.

It's being developed on two 68008 and one 68000 SBC that I have but I hope to have a version for the Amiga and other home computers eventually. There is even a version that runs on EASy68K. 8^)=

There are few hardware dependant routines, initialise timer, timer interrupt, initialise serial I/O, serial byte out, serial byte in and get serial Rx status.

I hope to have a version for release soon - house move permitting.

Lee.


Top
 Profile  
 
PostPosted: Tue Apr 11, 2006 2:18 pm 
Quote:
It's being developed on two 68008 and one 68000 SBC that I have but I hope to have a version for the Amiga and other home computers eventually. There is even a version that runs on EASy68K. 8^)=


It would be interesting (for me) to get a version running under Palm OS Garnet 5.4. A bit of support code to do terminal emulation (there must be some code out there to do it) then I can run it on my Fossil Abacus watch (Dragonball 66Mhz processor). You can't say that wouldn't be cool 8)

I can confirm that once relocated the standard Tutor 1.3 ROMs run on the MECB clone board, and TRAP #14 calls now work correctly. Next up is the tape interface. I'll post a URL when I managed to get a new domain name registered (my old one just expired!).

Out of interest, does anyone have any experience of interfacing a keyboard to the MECB or equivalent board? I am thinking of either (a) finding an old ASCII keyboard or (b) using a separate microcontroller to convert a PS/2 keyboard into RS232 compatible outputs.

Regards,

Mark.


Top
  
 
 Post subject:
PostPosted: Thu Apr 13, 2006 1:46 am 
Offline
User avatar

Joined: Thu Dec 16, 2004 6:42 pm
Posts: 1036
Location: Monroe County Community College, Monroe Michigan, U.S.A.
A standard PC keyboard will communicate with a serial interface. I've got the code somewhere that communicates with the PC keyboard via a 6850 ACIA. This was not a PS2 keyboard, I'm not sure what the voltage levels and signals look like on a PS2 keyboard.

_________________
Prof. Kelly


Top
 Profile  
 
 Post subject: Tape interface finished
PostPosted: Tue May 23, 2006 11:33 pm 
I've now tested my clone MECB tape interface replacement pcb and it worked first time!

Anyone interested please visit http://www.wickensonline.co.uk/mecb.html.

Regards,

Mark.


Top
  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group