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68K-MBC assembly instructions, setup and user guide?

rwcooper

Member
Joined
Jan 17, 2023
Messages
23
Hi, I just received a 68K-MBC full kit. I was expecting there to be instructions on assembly, setup and usage. I'm finding it very difficult to find any useful documentation on the 68K-MBC. If anyone can point me to online documentation regarding this or provide me with information I'd really appreciate it.

Thanks, Randy.
 

Pt68k5

Experienced Member
Joined
Feb 18, 2010
Messages
53
Have you looked at,
 

rwcooper

Member
Joined
Jan 17, 2023
Messages
23
Thank you for the link. It looks promising. I did find a link to this project on hackaday, but it was not as good as this one...Randy.
 

Harry.Speer

New Member
Joined
Dec 14, 2022
Messages
2
Regarding the 3-Chips 68008-based 68K-MBC - Is there any way to connect this to a bus ?? Something like the RC2014 or similar ?? Address Lines, Data Lines, Control Signals ?? To allow this SBC to connect and communicate with a second Card or Kit or ... ?? If not this one, Does anyone know of a different 68008 SBC Kit that > IS < Compatible with an expansion bus ?? Does not need to be compatible with other Z80-Based RC2014 Cards. Just use the Backplane ?? Example of a second card might be a DUART board with a 68681 DUART ?? Timing and handshake might only match between MC68k -Based Cards ??
 

Harry.Speer

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Dec 14, 2022
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2
Pt68k5 - Thanks Very Much for your posts. I did have the Mega-Micro page Bookmarked, and also the 68K-MBC "3-chips" board. And I have looked for and read all the Bill Shen Plasmo or Plasmode SBC projects I could find. And I have also read up on the whole ECB Bus which is sadly now dead. The S100 Google Group and Facebook S100 remain active thus my choice of S100 68008 SBC - project on a goal of a single S100 prototype board.

What I am wanting does not yet actually exist so far as I have found. I want to try to squeeze an MC68008 CPU with a single 512k x 8 Static RAM, and Something Similar to an EPROM that is roughly the same size internally. Both 512k x 8 - to hold BIOS, Monitor, and maybe CPM-68K in EPROM, etc. UART either a single or pair of 6850 UARTs or a single MC68681 Chip. A Power Socket for off-board 9V DC Wall-Wart and a 7805 or Switching Equivalent for +5V DC power. Goal = Stuff ALL of this in as small as possible space on a Single S100 prototype board. If I could get there, as an SBC, then look at the S100-Bus interface afterwards.

This idea is inspired by the Very-Recent Z180 SBC for S100 created by John Monahan - His S100Computers.Com website and he frequently posts on the S100 Google Group online. My idea is to "do the same thing" but this time with the 8-bit 68008 CPU. Smaller chip better for squeezing as much as possible onto the one S100 card which is about only 5-inches High by about 10-inches Wide. John already has the 68000 CPU / 68010 S100 Master/Slave card. The 16-bit version. Huge Chip. And both Odd and Even ROMs and RAMs. By using the 8-bit 68008 uses only a single RAM chip and a Single EPROM chip. John has the 68000 S100 card But it Does Not Have Either a UART or DUART. I hope by using the 8-bit CPU chip and the one-each RAM and EPROM, I hope that there will be enough room then to stuff in a Single UART or DUART and use the MAX232 chip or chips. Stick with 5-volts only where-ever possible. No +12 and -12 V Regulators for the MC1488 + MC1489 pair. "Tradition" says use the + & - 12V and the two MC 1488/89 chips. But keeping it all as small as possible says use the MAX232 or equivalent. The Z80 S100 SBC already exists. And the JAIR 8080 CPU SBC also exists. But I am a fan of the m68k. When I have looked around, the ROSCO 68000 motherboard comes closest. But the cards for the ROSCO bus are few. I started a long long time ago with the Altair8800b but using the SAGE 2 and SAGE 4 in College made me want my own 68000 Home-PC - not implying any relationship to the IBM PC. I owned a Xerox 820-2 with the 8088 Co-Processor Card. CPM-80 2.2 and also MS-DOS 2.0 on an 8-INCH Boot Floppy. I've spent 40 years on IBM PC descendants as an On-Site Xerox Computer Repair team and also the Xerox Computer Repair Depot Shop in Redmond, Washington IIRC. And spent decades of IBM PC Compatibles. 8080, 8085, and Z80, Z180, and Z280 are not attractive to me as I have already "Been There Done That". But that 40-years "Lust" for my own 68K Home Computer, Inspired by wanting a SAGE 2 or 4 Computer never died. I wanted my own Sage. Still Do. But in the S100 Bus.

I hope that all of the above gives you a very clear description of what I want and Do Not Yet Have - My Own SAGE-Equivalent Home Computer. And NO The 68K Apple Mac computers and the Amiga 68K Computers and the Atari ST 68k - All of those feel like "Gamer Machines" and NO I am NOT a Gamer. I only play Klondike-Style Solitaire. Like on Windows and Linux.
 

Pt68k5

Experienced Member
Joined
Feb 18, 2010
Messages
53
Harry, I would look at using the 52 pin version of the 68008 as it supports 4 meg of address space and is in a plcc package which uses less space
The kiwi is based on the 68008 https://www.ist-schlau.de/hardware.html
And also there is the Katy which is also using the 48 pin version https://www.bigmessowires.com/68-katy/
Mega-micro offers bore boards for the 68000 and the 6850 or the 68681 using a 16 bit eprom to hold bios and Cp/m all in one chip which would get you started and the are small, he has two different versions on 68000 cpu boards, one is the plcc version
 

Plasmo

Experienced Member
Joined
Aug 29, 2017
Messages
208
Location
New Mexico, USA
Harry,
S100 is enormous amount of board space! How do you feel about CPLD in board designs? CPLD saves lots of board space so what you want can be done in 2"x4" pc board if CPLD is involved. For 68000, the idea is eliminating 2 EPROM and use x16 DRAM and bootstrap from CF disk. So the core design is 3 chips (68000, DRAM, CPLD) + CF disk. A DUART can be added to the core design. It can be something like T68KRC (3"x4"), but smaller because the serial bootstrap EEPROM is replaced with existing CF disk.
Bill
PS, if you accept serial bootstrapping, then CPLD and DRAM can fit inside the footprint of DIP64 68000, so the core design is not bigger than DIP64 68000.
PPS, another small design is based on P90CE201 which is derived from 68008. Kuno fits in Arduino Mega enclosure.
 
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