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Home » RBC Forums » General Discussion » Plasmo's 68k pathfinder projects (68K, 68000, 68020, 68030, 68040, 100mm x 100mm pc board)
Re: Plasmo's 68k pathfinder projects [message #2667 is a reply to message #2666] Sat, 06 May 2017 20:53 Go to previous messageGo to next message
computerdoc is currently offline  computerdoc
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Hi Plasmo,
If the boards are that cheap then put me on the list for 2 boards please. I am following this Tiny68K with great interest.


Kip Koon
computerdoc at sc dot rr dot com
http://www.cocopedia.com/wiki/index.php/User:Computerdoc
Re: Plasmo's 68k pathfinder projects [message #2785 is a reply to message #2667] Mon, 15 May 2017 14:22 Go to previous messageGo to next message
etchedpixels is currently offline  etchedpixels
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Watching with interest.

For software CP/M 68K wasn't the only game in town. In fact it basically died the death. What rose from the ashes was the Atari TOS which was proprietary but has since been cloned as EmuTOS.

http://emutos.sourceforge.net/en/

while you aren't going to be able to run Atari ST games in your board there's a heck of a lot of command line TOS based tools and utilities, plus if you have enough memory GUI desktop apps that will.

Re: Plasmo's 68k pathfinder projects [message #2792 is a reply to message #2785] Tue, 16 May 2017 04:52 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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Received the pc board back. The turn-around time is 7 days. Built up the first board to develop CPLD equations. The state machine for serial EEPROM loader is somewhat complex and I don't have a simulator so I'm using the actual hardware to test out the CPLD code. It was going pretty well until my USB Blaster die right in the middle of the testing. It'll be a couple more weeks before I have the replacement.
All the Tinyxxx will run Lee Davison's Ehbasic. I'm impressed with Prof Chuck Kelly's EASy68k toolchain so I make them compatible with EASy68K. I have not tried CP/M 68K, mainly because I don't have IDE interface up till now. Tiny68K has the 44-pin CF IDE interface and 16megabyte of RAM, so I'm looking forward to port CP/M68K.
index.php?t=getfile&id=430&private=0

Re: Plasmo's 68k pathfinder projects [message #2797 is a reply to message #2792] Tue, 16 May 2017 09:15 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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I finally looked at your design and was struck by the similarities to mine. Except somewhere along the line, I switched from the MAX 7128 to the MAX-10 FPGA. And I'm using the 68SEC000 QFP instead of the old DIP version.

I am intrigued by your use of the serial ROM for booting. I thought about that but I wasn't sure I was capable of getting the MAX to load the RAM from it upon reset. So I'm looking forward to seeing how you accomplish that task.

Instead of a XBee and IDE, I'm going for UART, SD card, and Ethernet (via a EthClick module).

My board came out to be 5" square so a bit bigger. Full size SD card takes up a LOT of space!

index.php?t=getfile&id=431&private=0

I'm looking forward to seeing your's progress. good luck!



Mike
Re: Plasmo's 68k pathfinder projects [message #2801 is a reply to message #2797] Tue, 16 May 2017 12:23 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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My entire motivation for this design is cost reduction. I really want to see how close I can get to a $10 68000 SBC. So the design choice of serial boot flash on a marginally adequate 7128 are driven entirely by cost consideration. The 7128 design is entirely in schematic, including the state machines. With MAX10, it will be in Verilog which is much easier to code. In fact, serial boot flash is really unnecessary since MAX10 has quite a bit of on-board user flash so 8K bytes of boot code can easily fit in the on-board flash. You can get rid of your two external flash chips.

I want to have a data logger for my home XBEE network that's why XBEE is there. I rather have VGA & Ethernet (mini-ENC28J60) which I think is possible by using a PLCC 68000 and get rid of XBEE. All should still fit in a 100mm sq board, but one step at a time...

I really like the 100mm sq format because it forces design simplicity, rapid prototyping and spiral development cycle.

Re: Plasmo's 68k pathfinder projects [message #2802 is a reply to message #2801] Tue, 16 May 2017 12:51 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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Using a $25 7128s seems like it'll be hard to get to a $10 board. Smile The MAX-10 is only $17.50! Smile The 29 decoupling caps for the MAX-10 are a definite negative for it. Sad

If I tried using the MAX-10's user flash for the boot ROM image, then I'd either have to add the high 8 bits of the data bus to the MAX-10 using valuable pins or I'd have to copy the ROM contents to RAM like you're doing. Both approaches have risk involved since I haven't done anything significant with a FPGA before! With the external flash for the ROMs, I just need standard chip select functionality from the FPGA before I'd have a minimally working system. The plan is then to add SDRAM support, then a periodic timer, SDIO, and Ethernet. The ETHclick is based upon the ENC28J60 but on a little board with the RJ-45. Someplace along the way I hope to be running ucLinux.

I looked into adding DVI but I was 4 pins short! Sad But if I add video out, then I'd need USB in for keyboard and mouse. So I'd need even more pins! So I decided to put off video for either a daughter board, hence the two 40 pin headers, or for my "real" system.

Speaking of my "real" system, I discovered Coldfire v4/v4e processors last night. 200+ MHz 68000, MMU, FPU, SDRAM controller, PCI controller, UARTs, Ethernet, expansion bus, ... all in one little 388 pin BGA. Smile And NXP is still making them! Add KVM and that would make a nice system. Not very "retro" though.

Too many choices. Not enough money in the toy fund. Sad



Mike

[Updated on: Tue, 16 May 2017 12:53]

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Re: Plasmo's 68k pathfinder projects [message #2805 is a reply to message #2802] Wed, 17 May 2017 05:38 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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I bought my lifetime supply of 7128S a few years back at much lesser than $1 each. Admittedly it was an unusual circumstance and not representative of current price. I looked up EPM7128S on aliexpress and found them at about $2-$3 each in lot of 10 or 20. MAX family are very cool, I'd definitely use them for 3.3V designs.

Altera tools are fairly easy to use. Once you got used to them, you'll never go back to simple PLD like 22V10. I don't even own a PLD programmer. I may eventually get one only because that's what I needed to build most of the Retrobrew projects.

Coldfire is not fully compatible with 68000 instructions but close enough that microapl has a translator that converts 68000 code to Coldfire code. I used it before, it is quite good.

mikemac wrote on Tue, 16 May 2017 12:51

Too many choices. Not enough money in the toy fund. Sad


Amen!
Re: Plasmo's 68k pathfinder projects [message #2810 is a reply to message #2805] Wed, 17 May 2017 13:44 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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I guess I'm too much of an old fuddy duddy worrying about a deal "that's too good to be true" with the random Chinese or Russian suppliers on the net. So I've stuck to Digikey whenever possible. I know that if I ever build my 040 dream machine, that I'll have to bite the bullet and deal with the unknown sources.

As for the Coldfire, since I don't have any 68K binaries, being 100% 68K complete isn't that big of a deal for me. As long as GCC supports the processor and there's a reasonable chance of running Linux, I'm happy. I ran into the Coldfire on the http://firebee.org. It's a Atari ST/Falcon compatible so they're more interested in binary compatibility. Sounds like the Coldfire is good enough for them.

The bigger problem with the Coldfires is that they're essentially complete SoCs. They have just about everything already built in. So where's the fun in that? At that point, I just as well go with a modern ARM SoC running at GHz rates instead of 266 MHz old stuff.

Are you planning on writing your own SDRAM controller or are you going to use/modify one of the "open" implementations that are out there? I sketched out what I thought the VHDL should look like before I went looking. The ones I found pretty much matched what I was expecting. They all have different feature sets but the basics of talking to a SDRAM are the same.



Mike
Re: Plasmo's 68k pathfinder projects [message #2813 is a reply to message #2810] Wed, 17 May 2017 17:02 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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Some of those deals do seem amazingly cheap and too-good-to-be-true, but I have purchased and played with enough of them over the years that I've came to the conclusion that if the items do not work as expected, the problem is usually with me or my expectations.

I have not designed with SDRAM yet, so I don't know how complex the SDRAM controller would be. Tiny68K uses the old fashion 72 pin SIMM module with an array of 4meg x4 DRAM. The DRAM controller is pretty simple--just a clocked delay line controlling 11-bit address mux and a similar clock delay line generating CAS-before-RAS refresh. The DRAM controller uses 18 flip flops and the design for Tiny030 DRAM controller is here:
https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=b uilderpages:plasmo:tiny030:tiny030_cpld.pdf
Since the address mux is inside the 7128S now, the equivalent circuit for Tiny68K is even simpler than that of Tiny030.

Hark! I thought I've heard talks about 68008 on another line. It's getting interesting...
Re: Plasmo's 68k pathfinder projects [message #2942 is a reply to message #2813] Wed, 31 May 2017 17:20 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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This is embarrassing!
I received the replacement Altera USB Blaster last week. It works just fine so I'm ready to assemble the rest of the board, so I thought. Imaging my surprise when I realized DIP64 68000 is NOT 600mil wide! Embarrassed Instead it is 900mil wide. After a bit of denial and cursing I decided I can just solder one row, tilt the 900mil 68000 45 degree and connect the other row via wires. I don't suppose anyone would be interested in this version of the pc board now.
index.php?t=getfile&id=487&private=0
The good news is that I used the time waiting for USB Blaster to learn about Altera Quartus' native simulator. It is actually pretty decent and more than adequate for CPLD designs of modest complexity. I'm able to check out most of the serial EEPROM loader functionalities. It appears to be working--I'm able to load a small NOP loop code in serial EEPROM into DRAM, release reset and have 68000 execute it endlessly. A simple memory diagnostic checking part of the 16meg DRAM also works fine.

Between the DRAM controller, serial EEPROM loader, and address decoder I used up 95% of the logics in EPM7128--121 flip flops out of 128 available.

I program the 24C256 use a $5 USB CH341A serial EEPROM programmer. The toolchain for developing serial EEPROM bootcode in 68000 assembly is:
write & assemble code in EASy68K-->convert S Record to binary file with EASyBIN-->load the binary file with CH341A.exe and program the AT24C256 serial EEPROM.
EASy68K & EASyBIN are downloaded from easy68k.com
CH341A can be found from the download link of this youtube instruction on how to use EEPROM programmer:
https://www.youtube.com/watch?v=L0ChYNwunUE

[Updated on: Wed, 31 May 2017 17:35]

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Re: Plasmo's 68k pathfinder projects [message #2943 is a reply to message #2942] Wed, 31 May 2017 20:54 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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The 68SEC000 would save you a lot of board space! Smile

If you have to have a DIP, you can get a 64 pin QFP to DIP adapter from Digikey. And it is 0.6" row spacing. Smile I used a pair of standard 40 pin DIP sockets on my first board.

The local FPGA guru warned me about how fast the MAX CPLDs fill up. He has ulterior motives though, trying to get me to become a passable FPGA developer. Sounds like you're on your way to that goal! Congratulations!

BTW, is that a resistor I see holding pin 7 up?



Mike

[Updated on: Wed, 31 May 2017 20:56]

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Re: Plasmo's 68k pathfinder projects [message #2945 is a reply to message #2943] Thu, 01 June 2017 08:47 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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I designed with what I have and I have a number of 68000 in DIP64. Now I remembered it is 900 mil wide, I think I can actually save board space because the CPLD and DUART can fit under the chip freeing up the other half of the 100mm x 100mm board for video and Ethernet.

Yes, it is a 33 ohm serial terminating resistor at the source (address strobe) on pin 6. Early on I thought I had a possible glitch due to reflection, but it was instrumentation error.
Re: Plasmo's 68k pathfinder projects [message #2968 is a reply to message #2945] Mon, 05 June 2017 17:35 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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Its alive!
index.php?t=getfile&id=491&private=0
All 68000's 16 megabyte memory space is taken up with a 16meg SIMM module except the top 32K bytes which are allocated to 68681 (DUART), IDE, and the expansion edge connector. The DRAM should be fast enough to run at zero wait for the fastest 68000 (20MHz). I have a 68HC000P10 running at 8Mhz right now. The refresh logic is CAS-before-RAS running automatically invisible to the the 68000 by inserting wait state to DRAM access during a refresh cycle. The monitor is about 11K bytes. The serial EEPROM loader loads half (16K bytes) of the AT24C256 into low memory of DRAM at powerup or reset. The serial clock is 500KHz so it takes about 300mS to load the monitor, barely noticeable.

The monitor uses EASy68k trap #15 services for I/O so Lee Davison's EhBasic runs with very little modifications-- two changes: org to 0x4000 & disable DUART interrupts. I got the ASCII art program from tobster's hackaday page and I use it as a performance benchmark. The program takes 102 seconds to run on the 8MHz Tiny68k. It takes 29 seconds on Tiny030, 22MHz 68030.
index.php?t=getfile&id=492&private=0
I built up the board mostly with my existing inventory of parts, but since low cost is the main goal of this project, I look around eBay for 10pcs lot (shipping excluded) to find out how close it comes the $10 goal:

68HC000P10, $3
68681, $2
16meg SIMM72, $4
SIMM72 socket, $1.5
24C256, $0.4
Oscillator, $1
Altera EPM7128SQC100-15, $3
pc board, $0.5

So that's $15.4 for major parts and probably $2 for miscellaneous parts. Definitely over $10, but it is about $10 if you already have spare 68000, 16 mega SIMM, and miscellaneous parts,

Re: Plasmo's 68k pathfinder projects [message #2970 is a reply to message #2968] Mon, 05 June 2017 18:44 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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Congratulations! Looks impressive! I look forward to studying your MAX CPLD code. I'm sure I'll learn a lot.

While dreaming in the shower this morning, I was considering spinning your design to use the 68sec000 and other Digikey/Mouser parts. I must have been picking up the success you were having.

Are you going to port ucLinux to it now? Smile



Mike
Re: Plasmo's 68k pathfinder projects [message #2979 is a reply to message #2970] Tue, 06 June 2017 10:43 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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ucLinux is a huge jump for me. I used Unix once in a blue moon and never Linux. I'm taking baby step by first adding the Compact Flash IDE, then try porting CP/M68K or the EmuTOS suggested by etchedpixels. I'll respin the board to correct mistakes and add needed features, but this board may not be suited for Linux. I may change my mind later, but at this point I'm not particularly interested in Linux.
Re: Plasmo's 68k pathfinder projects [message #2986 is a reply to message #2979] Tue, 06 June 2017 12:06 Go to previous messageGo to next message
tingo is currently offline  tingo
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Nice progress! Is anyone going make a kit out of this?

Torfinn
Re: Plasmo's 68k pathfinder projects [message #2992 is a reply to message #2986] Tue, 06 June 2017 14:58 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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Are you only using half of the SIMM? Looking at the schematic, you have the high word (16b) and the low word (16b) of the SIMM connected to the 16b data bus of the 68K. Seems like you're either using half of the available memory or you're interleaving the 68K's word accesses. Since you're only using 2 of the 4 RAS signals, I'm leaning towards using half of the capacity. Your SIMM is probably bigger than the 16MB address range of the 68K so it doesn't matter if you are only using a fraction.


Mike
Re: Plasmo's 68k pathfinder projects [message #2997 is a reply to message #2986] Tue, 06 June 2017 18:11 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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tingo wrote on Tue, 06 June 2017 12:06
Nice progress! Is anyone going make a kit out of this?


I don't think anyone would be interested in this version of pc board because of a major error in the 68000 footprint. Once I make the correction, it will be available to anyone interested. One issue is that I'm very fond of Altera's 7128S (5V CPLD, abundant I/O pins, excellent development tools that's free, in-situ programmability, low cost and I happen to have a large supply on hand) which is a surface mount part. Many people have problems soldering this part. I suppose I can sell a board with 7128S already soldered & programmed, but that'll rob people the pleasure of building board from scratch.
Re: Plasmo's 68k pathfinder projects [message #2998 is a reply to message #2992] Tue, 06 June 2017 18:13 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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mikemac wrote on Tue, 06 June 2017 14:58
Are you only using half of the SIMM? Looking at the schematic, you have the high word (16b) and the low word (16b) of the SIMM connected to the 16b data bus of the 68K. Seems like you're either using half of the available memory or you're interleaving the 68K's word accesses. Since you're only using 2 of the 4 RAS signals, I'm leaning towards using half of the capacity. Your SIMM is probably bigger than the 16MB address range of the 68K so it doesn't matter if you are only using a fraction.


The 72-pin SIMMs I have are populated on one side only with eight 4megx4 (e.g. HY5117404) DRAM, so that's 16 megabytes. My understanding of one-sided 72-pin SIMM is that RAS0 goes with CAS0 (low byte) and CAS1 (high byte) and RAS2 goes with CAS2(low byte) and CAS3 (high byte). RAS1 & RAS3 are for the other side which is unpopulated. The way I map the memory is 0x0-0x7FFFFF to RAS0/CAS0/CAS1 while 0x800000-0xFF7FFF to RAS2/CAS2/CAS3. When refreshing all CAS0-3 and RAS0/RAS2 are activated which does created quite a current spike and need to be managed with bypass & filter caps plus multiple ground traces

[Updated on: Tue, 06 June 2017 18:18]

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Re: Plasmo's 68k pathfinder projects [message #3000 is a reply to message #2998] Tue, 06 June 2017 20:39 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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Thanks for the explanation.


Mike
Re: Plasmo's 68k pathfinder projects [message #3020 is a reply to message #3000] Thu, 08 June 2017 07:24 Go to previous messageGo to next message
adx is currently offline  adx
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What are the hardware requirements to program the Altera's in-situ. Is it reasonable or a $500 Altera specific programmer that's needed?
Re: Plasmo's 68k pathfinder projects [message #3022 is a reply to message #3020] Thu, 08 June 2017 08:27 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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The Altera USB blaster is dirt cheap. My old one died a month ago so I ordered 3 more on eBay:
http://www.ebay.com/itm/3Pcs-Programmer-For-Cpld-Fpga-Nios-J tag-Altera-Mini-Usb-Blaster-Cable-Module-I-Z-/262937625518
They are $9 plus $1.80 shipping (slow mail, 2+ weeks to deliver), so that works out to lesser than $4 each.
I took a snapshot of how it is used on my board this morning. To program it in-situ, I powered up the board, click the "start" button on the Altera programmer software and it will reprogram the chip in 10-20 seconds. I leave the USB blaster connected as I debug because I can reprogram the Altera part over and over again bringing out internal signals to spare outputs to help me debug. I believe you can reprogram the part many hundreds of times.
index.php?t=getfile&id=497&private=0
Re: Plasmo's 68k pathfinder projects [message #3030 is a reply to message #3022] Thu, 08 June 2017 10:08 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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Argh! Your progress has inspired me to go back and look at my MAX10 based 68K design. And I just noticed that somewhere along the design process, I dropped D8 from connecting to the MAX10! Going to make it hard to implement all of those soft I/O devices in the FPGA without the low data bit! Sad


Mike
Re: Plasmo's 68k pathfinder projects [message #3047 is a reply to message #3030] Fri, 09 June 2017 14:34 Go to previous messageGo to next message
nealcrook is currently offline  nealcrook
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>> I built up the board mostly with my existing inventory of parts

I get the feeling that looking through your "junk box" would be quite exciting. Thanks for sharing all the details of your builds. I even got lured into buying a 68020 on ebay, to go with the 68000s and 68008 I already have sitting in my own, modest, junk box.

Neal.
Re: Plasmo's 68k pathfinder projects [message #3050 is a reply to message #3047] Sat, 10 June 2017 09:45 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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I do have a sizable collection of Motorola 68xxx processors & peripherals thus my interest in building them. I've always considered 68xxx along with National's 32xxx as having the best computer architectures of their times. It is a pleasure tinkering with these processors.
Re: Plasmo's 68k pathfinder projects [message #3051 is a reply to message #3050] Sat, 10 June 2017 10:04 Go to previous messageGo to next message
lynchaj is currently offline  lynchaj
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Interested in NS32K projects?
Re: Plasmo's 68k pathfinder projects [message #3052 is a reply to message #3051] Sat, 10 June 2017 11:27 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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lynchaj wrote on Sat, 10 June 2017 10:04
Interested in NS32K projects?


Yes and I've followed the discussion closely. BUT...I don't meant to be critical, but I thought it is too ambitious, at least for me. Since we are just dipping our toes in the NS32K processors, I thought we should start simple, small & cheap and experiencing the architecture of 32xxx at ground level. NS32008 with NS32202, DUART, RAM, Flash, CPLD, & IDE44 should fit in a cheap 100mm x 100mm 2-layer board. That's sufficient to learn NS32K assembly language, write a monitor/debugger in assembly and graduate to some sort of disk operating system. In fact, I already have a small hoard of NS32008 and I've contacted John Coffman to see if I can buy some NS32202 so I can pursue a simple, small, cheap solution. I know I'm not being a team player going off by myself like this, but NetBSD & high level language seem such a big leap and so disconnected from the heart & soul of 32xxx architecture, IMHO
Re: Plasmo's 68k pathfinder projects [message #3053 is a reply to message #3052] Sun, 11 June 2017 00:19 Go to previous messageGo to next message
pbirkel is currently offline  pbirkel
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plasmo wrote on Sat, 10 June 2017 11:27
I thought it is too ambitious, at least for me. Since we are just dipping our toes in the NS32K processors, I thought we should start simple, small & cheap and experiencing the architecture of 32xxx at ground level. NS32008 with NS32202, DUART, RAM, Flash, CPLD, & IDE44 should fit in a cheap 100mm x 100mm 2-layer board. That's sufficient to learn NS32K assembly language, write a monitor/debugger in assembly and graduate to some sort of disk operating system. In fact, I already have a small hoard of NS32008 and I've contacted John Coffman to see if I can buy some NS32202 so I can pursue a simple, small, cheap solution.


FWIW, this is the entry-level that I'd like to eventually pursue, as well.
"experiencing the architecture of 32xxx at ground level" is a great summary statement :->!
Re: Plasmo's 68k pathfinder projects [message #3054 is a reply to message #3052] Sun, 11 June 2017 07:10 Go to previous messageGo to next message
lynchaj is currently offline  lynchaj
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plasmo wrote on Sat, 10 June 2017 14:27
lynchaj wrote on Sat, 10 June 2017 10:04
Interested in NS32K projects?


Yes and I've followed the discussion closely. BUT...I don't meant to be critical, but I thought it is too ambitious, at least for me. Since we are just dipping our toes in the NS32K processors, I thought we should start simple, small & cheap and experiencing the architecture of 32xxx at ground level. NS32008 with NS32202, DUART, RAM, Flash, CPLD, & IDE44 should fit in a cheap 100mm x 100mm 2-layer board. That's sufficient to learn NS32K assembly language, write a monitor/debugger in assembly and graduate to some sort of disk operating system. In fact, I already have a small hoard of NS32008 and I've contacted John Coffman to see if I can buy some NS32202 so I can pursue a simple, small, cheap solution. I know I'm not being a team player going off by myself like this, but NetBSD & high level language seem such a big leap and so disconnected from the heart & soul of 32xxx architecture, IMHO


Without an MMU there is no VM and no hope of NetBSD or any other sophisticated operating system. Its essentially just another 8 bit microcontroller with a neat 32 bit ISA. Interfacing to the outside world though is still just 8 bits. If you want to do that its OK but its not where my interests are.

I think NS's original goal was sophisticated operating systems which seems pretty obvious from their ISA, datasheets, and application notes. I think they settled for embedded controllers when Intel and Motorola beat them to market. I think the PC532 or something like it (Symmetric 375) is the way to go.

Good luck with your project though. Andrew Lynch
Re: Plasmo's 68k pathfinder projects [message #3056 is a reply to message #3054] Sun, 11 June 2017 10:40 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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Clearly I have a lot to learn.

[quote title=lynchaj wrote on Sun, 11 June 2017 07:10]plasmo wrote on Sat, 10 June 2017 14:27
lynchaj wrote on Sat, 10 June 2017 10:04
Interested in NS32K projects?


Good luck with your project though.


Thanks!
Re: Plasmo's 68k pathfinder projects [message #3057 is a reply to message #3056] Sun, 11 June 2017 11:11 Go to previous messageGo to next message
davetypeguy is currently offline  davetypeguy
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Plasmo wrote: "I've contacted John Coffman to see if I can buy some NS32202 so I can pursue a simple, small, cheap solution ..."

In case John doesn't want to part with too many of the NS32202 chips (he has them for building the PIC boards, after all), you can get the NS32202N-10G from Quest Components. They have a large stash of them, and they aren't expensive. I bought a few myself recently while getting some other ICs.

http://www.questcomp.com/questdetails.aspx?pn=NS32202N-10G&a mp;mpid=433021897&pt=4

Dave
Re: Plasmo's 68k pathfinder projects [message #3058 is a reply to message #3057] Sun, 11 June 2017 22:28 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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Thank you for the link, it is downright cheap! In quantity of 5 to 15 it is 99 cents each , wow!
Re: Plasmo's 68k pathfinder projects [message #3137 is a reply to message #3058] Sun, 02 July 2017 16:20 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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Hey, I may have a CP/M 68K v1.3 working on my Tiny68K!
pictured here: https://www.retrobrewcomputers.org/forum/index.php?t=msg& ;th=152&goto=3022&#msg_3022

"DIR" gets me this listing:
index.php?t=getfile&id=526&private=0

"ED.REL Hello.txt" and "DDT.REL" get me this:
index.php?t=getfile&id=527&private=0

I've never had a CP/M computer so I'm unfamiliar with the various commands and functions. I feel like a kid on Christmas morning opening his first computer.
I'm following the instructions of "CP/M-68K operating system System Guide", modifying the sample BIOS to fit my serial device and CompactFlash and uploading the BIOS along with cpm15000 S-Record. The kludgy part was moving CP/M distribution files downloaded from http://www.cpm.z80.de/download/68kv1_3.zip into a CompactFlash and convert into CP/M directory format on my Tiny68k.
Still many things to check out, but I've cracked open the door and the world beyond bckoning!
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Re: Plasmo's 68k pathfinder projects [message #3138 is a reply to message #3137] Sun, 02 July 2017 16:52 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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Some performance specs:
- The 68000 is running at 8MHz, serial port is 38.4k baud.
- Power consumption is 350mA at 5V.
- Memory access to the 16meg DRAM is zero wait state.
- Compactflash IDE is bus connected with 1 wait state access.
- CF (SanDisk as pictured) read access is 250K bytes/sec, write access is 45K bytes/sec.
- All 9 floppy disks from the CP/M v1.3 are copied into drive A which is 8 megabyte, block size of 2048 bytes and 512 directory entries.
- I allocated most of the 16meg memory for TPA which is from 0x20000 (just above CP/M) to 0xE20000, about 14 megabytes.
- Since this is my first CP/M machine, I have no speed reference. "DIR" command responds immediately, the bottleneck is the 38.4kbaud serial port. Is there a benchmark I can run against?
- I have not figured out how to block/deblock 128 byte/sector of CP/M into 512 byte/sector of the CF, so each 128-byte CP/M sector takes a full 512-byte CF sector--very wasteful, something to work on in the near term.
Re: Plasmo's 68k pathfinder projects [message #3140 is a reply to message #3138] Sun, 02 July 2017 21:18 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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Congratulations! At this point, I can only imagine the joy of seeing your creation come to life, opening up a new world to explore and play in.

I've never actually used CPM either. Somehow just missed that whole thing. Almost got to 25-30 years ago with a Big Board but the 74138 was bad and the 8" floppies wouldn't work. So I wussed out and went back to Suns and Lisp Machines.



Mike

[Updated on: Sun, 02 July 2017 21:28]

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Re: Plasmo's 68k pathfinder projects [message #3141 is a reply to message #3140] Sun, 02 July 2017 21:27 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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I just read your updated Design page. I thought you were originally going to program the serial PROM through the USB Blaster. But I see you're now using an external programmer and that the serial PROM is socketed. Other than being easier to use the external programmer, was there a problem using the USB Blaster?


Mike
Re: Plasmo's 68k pathfinder projects [message #3143 is a reply to message #3141] Mon, 03 July 2017 10:17 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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Perhaps you are thinking of the Altera serial PROM (such as the EPC1) needed to program their FPGA devices such as Cyclone? The EPC1 is designed to interface with Altera's USB Blaster. Tiny68K uses Altera's EPM7128 which has internal flash memory and can be programmed in-situ with an USB Blaster. Tiny68K does have a serial EEPROM,AT24C256, but it is used to store up to 32K bytes of 68000 boot program which is loaded into DRAM while 68000 is held in RESET. AT24C256 is not compatible with USB Blaster and I was thinking of building my own AT24C256 programmer, but when a working programmer can be purchased for lesser than $10, it is hard to justify the extra efforts.
Re: Plasmo's 68k pathfinder projects [message #3144 is a reply to message #3143] Mon, 03 July 2017 13:03 Go to previous messageGo to next message
mikemac is currently offline  mikemac
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Nope. I had thought you had figured out a way to program the AT24C256 in place through the MAX7000 using the USB Blaster. Similar to how you can flash some of the external configuration PROMs through some of Altera's FPGAs. I thought that would be a nifty trick to know if you had. I guess for the time being we're still stuck with socketed boot ROMs.


Mike
Re: Plasmo's 68k pathfinder projects [message #3145 is a reply to message #3144] Mon, 03 July 2017 15:01 Go to previous messageGo to next message
plasmo is currently offline  plasmo
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Your comment triggered 2 thought processes:
The first one is the ability to re-program the at24C256. This is later than the version of EPLD design files I uploaded: I added bit-bang registers controllable by 68000 for at24C256's SCL(clock) & SDA(data), so now an updated software can be downloaded into 68000, test to make sure it works and then 68000 can updates the at24c256 via the bit-bang registers. Of course if the updated software has a serious bug, it is back to removing the serial EEPROM and programming it on a programmer.

The 2nd thought is use Altera EPC1 for serial EEPROM instead. I already have an Altera JTAG programming header so it is easy to add the EPC1 into the scan chain. I should be able to convert the serial bit stream into 16-bit parallel data and write it into DRAM--I've already done that with at24c256. The part I don't know is whether Quartus software can take 68000 binary or S record and convert that to .mif file and program it into EPC1. If all that work out, boot software development looks like this:
68000 Assembler/compiler --> s record --> Altera .mif -->load into EPC1 via USB blaster -->boot!
Re: Plasmo's 68k pathfinder projects [message #3151 is a reply to message #3145] Tue, 04 July 2017 09:18 Go to previous messageGo to previous message
norwestrzh is currently offline  norwestrzh
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Hey Plasmo --

Welcome to the wonderful (and sometimes very strange) world of 68k CP/M!

>> - I have not figured out how to block/deblock 128 byte/sector of CP/M into 512 byte/sector of the CF, so each 128-byte CP/M sector takes a full
>> 512-byte CF sector--very wasteful, something to work on in the near term.

If you have an e-mail addr., I can send you a copy of my BIOS that does the block/deblock. Works quite well on my 12 MHz 68k (all TTL - no programmable devices (except EPROMs)Wink. Too big to post here. It only supports 4 "drives" on the CF, however. You will have to agree not to laugh too hard (I'm a lousy 68k assembler programmer), and to send me your updates when you improve it. *grin*

Roger
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