Return-Path: Delivered-To: craig@sbc-85.com Received: from gator4254.hostgator.com by gator4254.hostgator.com with LMTP id 0HUDNDUIHGPQaQAAcizydQ (envelope-from ) for ; Fri, 09 Sep 2022 22:44:53 -0500 Return-path: Envelope-to: craig@sbc-85.com Delivery-date: Fri, 09 Sep 2022 22:44:53 -0500 Received: from [24.20.173.51] (port=54514 helo=smtpclient.apple) by gator4254.hostgator.com with esmtpa (Exim 4.95) (envelope-from ) id 1oWrQL-000IYn-Hf; Fri, 09 Sep 2022 22:44:53 -0500 Content-Type: multipart/alternative; boundary=Apple-Mail-64B505FF-BED9-4BFE-8444-F30FC9C53EC2 Content-Transfer-Encoding: 7bit From: SBC-85 Mime-Version: 1.0 (1.0) Subject: Re: SBC-85 plus new project board Message-Id: <10A80F88-7387-4399-AB2B-0E8E6EB41AEB@sbc-85.com> References: <01c101d8c4c4$7575fb10$6061f130$@jjwhitney.com> In-Reply-To: <01c101d8c4c4$7575fb10$6061f130$@jjwhitney.com> To: john@jjwhitney.com Date: Fri, 9 Sep 2022 20:44:52 -0700 X-Mailer: iPhone Mail (19G82) --Apple-Mail-64B505FF-BED9-4BFE-8444-F30FC9C53EC2 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable I need yo make anew CPU board anyway. In fact I need to make two since I hav= e never gotten around to building a quad flat pack surface mount version I m= ade some boards for last year.=20 If the weather is hood here and the smoke goes away I hope to be gone much o= f the month. =20 My mailing address is Craig andrews 13500 ne 259th street Battle ground WA 98604 If the other ports are working perfectly, I don=E2=80=99t think the problem c= an be the decoding glue since (except for one gate) the glue that decides th= e UART also decides other ports.=20 It can=E2=80=99t be A8 since the PPI uses that line also.=20 It can=E2=80=99t be the /RD or /WR since the otheff TV ports use the same=20= It can be the reset or clock since those are critical yo the UART. the PPI u= ses the reset but it isn=E2=80=99t as finicky as the UART which must get its= commands immediately following a reset.=20 I wonder if there is a bug in the software? You are using just my diagnosis m= onitor and manually writing to the ports or have you tried writing code for t= hat? Have you tried removing the other port chips like the PPI and U13? What is the possibility you have dead / fake UARTs? To make sure the PCB is ok you could remove the chips and make sure the sign= als to the UART are correct and nothing is open or shorted to ground. It is v= ery uncommon but not unheard of to have defective boards.=20 Regards Craig > On Sep 9, 2022, at 8:22 PM, john@jjwhitney.com wrote: >=20 > =EF=BB=BF > I can send you one of the SPIO and a V2.0 CPU if you would rather not buil= d a new one. Let me spend time this weekend looking at a few things to see w= hat I find. I have a version 1 CPU board that I routed the reset line to the= edge connector so that will be the first test. I will check the V 2 board f= or the reset pin connection to see if that is a problem as well. > =20 > Send me your mailing address and I can send the boards out next week, than= ks. > =20 > Jack > =20 > From: SBC-85 =20 > Sent: Friday, September 09, 2022 11:08 PM > To: john@jjwhitney.com > Subject: Re: SBC-85 plus new project board > =20 > Oh. I was sort of hoping that was the problem. I don=E2=80=99t think the= 8251 could keep up with the 6 mhz 8085 but the 8251A should be fine. > =20 > I will keep digging. Let me know if you want to send me one of the duds to= look at. =20 > =20 > If I had only one piece of test equipment, it would be my saleae logic ana= lyzer.=20 > =20 > Did you check the reset line? I thought that every v2.0 board had it conne= cted but I watched my SPIO video and there I mentioned the first v2 CPU boar= ds did not use the reset. I don=E2=80=99t know if that is correct or not bu= t it is worth checking. In the users manual, it says that connected with the= very first version 2.0 so it is unlikely to be the problem.=20 > =20 > Let me know if you come up with any additional insight. > I need to clean the intellec 8 system off my bench and make room to make a= SBC-85 cpu and solve this problem or at least come up with some good diagno= stic tests. > =20 > Regards > Craig >=20 >=20 > On Sep 9, 2022, at 7:49 PM, john@jjwhitney.com wrote: >=20 > =EF=BB=BF > I=E2=80=99m using the 8251A on all boards. > =20 > JW > =20 > From: SBC-85 =20 > Sent: Thursday, September 08, 2022 11:56 PM > To: john@jjwhitney.com > Subject: Re: SBC-85 plus new project board > =20 > Writing commands and getting response should be fundamental, you are right= that is the place to start. > =20 > Are you using 8251 or 8251A? > =20 > You have I/o with the PPI, so Board decoding must be ok but if you can con= firm /CE with a scope or logic probe that would be worth the effort. > Can you put a scope or logic probe on and make sure /rd /wr reset A8 are t= he same on the UART and PPI? > Do you have a good CLK at the UART? The PPI doesn=E2=80=99t need a CLK, b= ut the UART needs it to work.=20 > =20 > =20 >=20 >=20 >=20 > On Sep 8, 2022, at 3:26 PM, john@jjwhitney.com wrote: >=20 > =EF=BB=BF > Hi Craig: > =20 > I had the chance to try the SPIO board today and can not get the seri= al port to work. The other ports work as expected but I get no response from= the 8251 when I send data to it. I used the confidence test to send data to= the port and the response back was all zeros where your documents show diff= erent responses. When I do an input to the control register of the 8251 I ge= t only zeros back. I tried two different boards and 3 different 8251 chips w= ith the same results each time. > =20 > I do not know what to try next. Any suggestions? > =20 > Jack > =20 > From: craig@sbc-85.com =20 > Sent: Wednesday, September 07, 2022 6:28 PM > To: john@jjwhitney.com > Subject: RE: SBC-85 plus new project board > =20 > Hi Jack, > I see another tindie order including the SPIO. Are you still having tro= uble getting those going properly? Maybe I need to take some time to look in= to it and see what could be going wrong? if you are having troubles, let me= know what you are seeing and maybe I can figure out what is going on. > =20 > regards > =20 > craig > =20 > From: john@jjwhitney.com =20 > Sent: Sunday, August 7, 2022 1:14 PM > To: craig@sbc-85.com > Subject: RE: SBC-85 plus new project board > =20 > Hi Craig: > =20 > Glad to hear you are back at it. I never got the original bus monit= or to work 100%, had trouble with the single stepping, so I decided to try t= he new version of the board. I really like the idea of having a front panel w= ith flashing LEDs. I retired last month and will be looking for things to ke= ep busy and building boards is something I enjoy, at least as long as I can s= ee up close. > =20 > I never got the serial port to work. I think it had to do with hand s= haking, I gave it some thought and when I try again I will tie CTS & RTS tog= ether on both ends and see if that works. I haven=E2=80=99t look at the code= in maybe two years so it will take me some time to get back into it and kno= w what I=E2=80=99m doing. > =20 > If you have an extra STD-bus board I can take a look and see what I c= an do with it. I have no experience with that interface so the board would b= e operated in stand alone configuration. I watched the video you sent and wi= ll have to look up the project to get additional info. Thanks for the offer a= nd I hope I can help with the project. Let me know if I can help down the ro= ad. > =20 > Jack > =20 > From: craig@sbc-85.com =20 > Sent: Sunday, August 07, 2022 12:58 PM > To: john@jjwhitney.com > Subject: SBC-85 plus new project board > =20 > Hi Jack, I see you got another bus monitor board from tindie. > =20 > Did we finish up this discussion / problem on the SPIO board or did I drop= off the edge of the earth? I am trying to remember last august---since aug= ust can be good flying weather, sometimes when I come back from a long trip,= I totally forget where I was > =20 > If you would use it, I can send you one of the new STD-85 boards I just fi= nished. it is STD-bus but it has a few fun features and I could always use y= our help finding problems with the board / software / documentation. > =20 > {93} STD Bus 8085 Single Board Computer First Round of Testing--Getting to= know the STD-85 - YouTube > =20 > if you need another project, I can toss it into the envelope. Or, if you= are looking for a real change of pace, I think I have one of my F8 boards l= eft I could send. > =20 > let me know > =20 > best regards, > =20 > craig > =20 > From: john@jjwhitney.com =20 > Sent: Sunday, August 8, 2021 5:31 AM > To: 'craig Andrews' > Subject: RE: SBC-88 > =20 > Hi Craig: > =20 > My most recent projects include a Z80 CP/M system based on the RC2014= platform as well as the Glitch works 8085 CP/M system. I just got the Z80 w= orking this weekend and finding a lot of cool stuff from the 1980=E2=80=99s a= gain. The storage system is a 64MB compact flash drive and the 100 pin bus h= as many different cards to add to it. The Glitch works 8085 is a bit more li= mited but has some expansion capabilities. Over all I think your bus structu= re is better and if you have thoughts of adding a compact flash card for sto= rage they are fairly easy to implement. Only problem is the fine pitch surfa= ce mount card holder. > =20 > One other project is I am trying, yet again, to grow Bonsai trees. It= is a fascinating hobby but very challenging to start a tree from a seed and= have it grow to a sustainable size. I have had success in germinating a few= trees only to have them all die at some point, some lasting many months but= all seem to succumb to neglect. Maybe as I get in to retirement I will have= more time to pay attention to them. > =20 > As for the needed corrections, I still could not get the 8251 on the S= P/IO board to work. Might have something to do with CTS/RTS signals but I=E2= =80=99m not sure. I am looking forward to reviewing you future projects so p= lease let me help when you need a second pair of eyes. Stay healthy and prod= uctive and I look forward to hearing from you soon. > =20 > Jack Whitney > =20 > From: craig Andrews =20 > Sent: Wednesday, August 04, 2021 11:48 PM > To: john@jjwhitney.com > Subject: Re: SBC-88 > =20 > Hi Jack, it is good to hear from you. I am slowly getting back into thing= s but have not been working on electronics much. For some reason starting (= and then finishing) projects seem like a major hurdle. > =20 > If you have come across any things in the documentation that I need to add= ress, please let me know. Those are little projects that are easy for me to= get traction.=20 > =20 > I cannot remember if I caught up on all corrections on the hardware like t= he dangling ground you found on the serial port. So let me know if you are s= eeing any hardware problems too. =20 > =20 > If you are looking for software projects, the version of tiny basic on the= sbc-85 site is still incomplete. > =20 > yes, there is a lot of good, clean fun left in the 8085 still yet. > =20 > What projects are you up to? > =20 > Regards > =20 > Craig > =20 > On Aug 4, 2021, at 7:02 PM, john@jjwhitney.com wrote: >=20 > =EF=BB=BF > Hi Craig: > =20 > Long time since we last connected. So glad you are better now and wis= h you the best moving forward. I was a bit worried since you went from a pro= lific poster to nothing so suddenly. Sorry to hear about you contacting Covi= d-19, I hope you are fully recovered or close to it. I know I asked about th= e 8088 system before but now I=E2=80=99m hooked on the 8085 and built a few d= ifferent versions and having a lot of fun. Thanks for sending me down that r= oad as I have learned a lot along the way. > =20 > Take care and keep me informed of your next project. I wish you all t= he best. > =20 > Jack Whitney > =20 > From: craig.andrews@tessol-inc.com =20 > Sent: Friday, September 11, 2020 7:43 PM > To: john@jjwhitney.com > Subject: RE: SBC-88 > =20 > Just discovered there is a mistake in the SBC-85 v2 > =20 > Pin 5 of the DB9 was left floating, that needs to be taken to ground > =20 > Regards > =20 > Craig > =20 > =20 > From: john@jjwhitney.com =20 > Sent: Sunday, August 23, 2020 6:51 AM > To: guus.assmann@wolmail.nl > Cc: craig.andrews@tessol-inc.com > Subject: RE: SBC-88 > =20 > Hi Guus: > =20 > I was able to look at the items you sent. As for the buss structure I= believe it will work as described. The only change would be to change the T= RAP pin to NMI and connect the NMI pin to it. Both have the same function on= their respective CPU=E2=80=99s, just the naming difference. > =20 > I downloaded the KiCad program and am working on a new schematic for t= he 8088 circuit. It will take me a while as I have to learn how the program w= orks and how to make it all look good. > =20 > As for the circuit, I am not a fan of using a Mega chip in support of= the design. Reason is simple, I am more of an old school design type. With t= he expansion capability of the SBC-85 bus design I see the possibility of re= creating an IBM clone type of system if someone so desires. As with any old t= ime CPU design the question of why comes to mind and I say because there is a= lot to learn from the old stuff and it is far more simple to build than any= new concept. > =20 > Give me a few days to discover the KiCad program and I will try to ge= t the CPU schematic design done. =46rom there I will look into a circuit boa= rd design as well. I am a fan of using four layer PC boards even though they= are more expensive to build. I like the grounding effects the internal laye= rs provide and not having to route the power and ground lines helps keep the= number of feed through holes to a minimum. Please keep in mind that these a= re my preferences and not an absolute for or against any other design. By us= ing a common bus it is possible for the universe of potential designs to coe= xist and the use of various expansion boards to be built. Keep in touch and t= hanks for the input. > =20 > Jack > =20 > From: guus.assmann@wolmail.nl =20 > Sent: Saturday, August 22, 2020 1:46 PM > To: john@jjwhitney.com > Cc: craig.andrews@tessol-inc.com > Subject: RE: SBC-88 > =20 > Hello Jack, > =20 > Thanks for the reply. > Great that you're also willing to participate. > I've done quite a bit of PCB routing, so that's not the problem. > However it's always good if someone can check the stuff I've done. > I've printed the schematics from KiCad. (It's a free program, so you might= want to download it anyway.) > The schematics were taken from a Hackaday project. I'll put those schemati= cs in the mail as well. > First thing that would help a lot, is if you can compare the two schematic= s and also have a look at the project on Hackaday. > =20 > Why did I select this? > Well, the hackaday project has been tested and has a lot of software. > Using the ISP interface on the Atmel Mega is not too complicated. > But of course, one of the Ram's can be replaced bay an Eprom. > And for that Hackaday project, there's a PCB, so I can test that PCB and t= he one I've made. > It has an IIC bus for adding a RTC and an SD-interface. > But I thing the PCB-design is compattible enough to fit to the SBC-Bus. > Also a lot of RAM and any Eprom content can come from the Mega, fetching i= t from the SD-card. So very flexible. > Still, I/O can be added with the bus. And the RS232 interface can stay on a= s well. All parts do fit the PCB. The only thing I've not put on (yet) is th= e IIC-expander MCP23017. > This design doesn't need the 8284 clock chip and the Mega does the Uart st= uff. > =20 > One more thing I've done as preparation is make a document on the expansio= n bus connector. We need to determine the signals and what to add on the bus= . The where to add it should be a bit logical as well. But routing is not al= ways so easy.... > Could you also please check these two documents. There's something missing= still, I've not added all the stuff. > =20 > Anyway, think about it. > And please don't hold back on feedback. (It's also ok if you don't like it= at all.) > In that case, we'dd have to think of something else. > I started out with a Z80 design, but this 8088 seems much easier as it has= most of the 8085 signals available. (And =C3=8D've ordered the hackaday PCB= for a very nice low price. A total of 10 Euro including shipment, so it can= be used as a reference design.) > Using the memory expansion card on the SBC-85 design should also not be ve= ry difficult. > =20 > BR/ > Guus Assmann > =20 > Op 22 augustus 2020 om 17:31 schreef john@jjwhitney.com: >=20 > Hi Guus: >=20 > =20 >=20 > I can not open the files you sent as I do not have the proper schemat= ic program. That said What I was thinking was a simple 8088 circuit with the= 8284 clock chip, 62256 32K ram, 27256 eprom with a 74LS573 to decode the ad= dress bus. An 8251A USART is desired with it all using Craig=E2=80=99s SBC-8= 5 bus with the extra signals added to accommodate the extra address lines of= the 8088. It should all fit on a board about 100mm X 100mm like the SBC-85.= >=20 > =20 >=20 > I believe the V20 chip you use handles both 8085 and 8088 instruction= s so that looks like a good possibility. As of today I do not have the board= design capabilities and if I did I am not very good at board design. I can r= eview any schematic if I can get them in a PDF version so I can open it. Ove= rall I am not looking for anything more than a hobby edition and having it a= vailable as open source is desirable. Let me know how I can help and it=E2=80= =99s great to meet another enthusiast. >=20 > =20 >=20 > Jack >=20 > =20 >=20 > From: guus.assmann@wolmail.nl =20 > Sent: Saturday, August 22, 2020 9:57 AM > To: craig.andrews@tessol-inc.com; john@jjwhitney.com > Subject: Re: SBC-88 >=20 > =20 >=20 > Hello, >=20 > =20 >=20 > Have been bussy. >=20 > Sorry for not consulting first, so please regard this as a proposal. >=20 > More information will follow. >=20 > =20 >=20 > BR/ >=20 > Guus Assmann >=20 > Op 22 augustus 2020 om 1:35 schreef craig.andrews@tessol-inc.com: >=20 > Hi Jack and Guus >=20 > =20 >=20 > By way of introduction, you have both expressed interest in developing an 8= 088 version to the SBC-8x ecosystem. Guus has started the development of a Z= 80 version so I have sent him the 8085 CPU board kicad files as a starting p= oint, I can also send these to you Jack. Since I have no plans to create an= 8088 CPU it would be fantastic if you two wanted to work together on this. = I suspect that if you create a hackaday project you could find others to jo= in since I have been asked many times if I am planning an 8088, Z80, and 650= 2 versions, or if you prefer I can create the hackaday project and you can j= oin as team members. The short answer is that I am not planning on developi= ng any other CPU board but strongly encourage others to add to the ecosystem= and will support that effort to the extent I am able. >=20 > =20 >=20 > I look forward to new hardware for the SBC-8x ecosystem and hope this come= s to fruition. >=20 > =20 >=20 > Best regards >=20 > =20 >=20 > Craig >=20 > =20 >=20 > =20 >=20 >=20 > =20 >=20 >=20 > =20 --Apple-Mail-64B505FF-BED9-4BFE-8444-F30FC9C53EC2 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
I n= eed yo make anew CPU board anyway. In fact I need to make two since I have n= ever gotten around to building a quad flat pack surface mount version I made= some boards for last year. 
If the weather is ho= od here and the smoke goes away I hope to be gone much of the month.  &= nbsp;

My mailing address is=

Craig andrews
13500 ne 259th street
Battle ground WA 98604=

If the other ports are wor= king perfectly, I don=E2=80=99t think the problem can be the decoding glue s= ince (except for one gate) the glue that decides the UART also decides other= ports. 

It can=E2=80=99= t be A8 since the PPI uses that line also. 

<= /div>
It can=E2=80=99t be the /RD or /WR since the otheff TV= ports use the same 

I= t can be the reset or clock since those are critical yo the UART. the PPI us= es the reset but it isn=E2=80=99t as finicky as the UART which must get its c= ommands immediately following a reset. 

I wonder if there is a bug in the software? You are using j= ust my diagnosis monitor and manually writing to the ports or have you tried= writing code for that?

Hav= e you tried removing the other port chips like the PPI and U13?

What is the possibility you have dead /= fake UARTs?

To make sure t= he PCB is ok you could remove the chips and make sure the signals to the UAR= T are correct and nothing is open or shorted to ground. It is very uncommon b= ut not unheard of to have defective boards. 

=
Regards
Craig

On Sep 9, 2022, at 8:22 PM, john@jjwhitne= y.com wrote:

=EF=BB=BF

I can send you one of the SPIO and a V2.0 CPU if you would rather n= ot build a new one. Let me spend time this weekend looking at a few things t= o see what I find. I have a version 1 CPU board that I routed the reset line= to the edge connector so that will be the first test. I will check the V 2 b= oard for the reset pin connection to see if that is a problem as well.<= /o:p>

 

= Send me your mailing address and I can send the boards out next week, thanks= .

 

Jack

 

<= div style=3D"border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0i= n 0in">

From: SBC-85 <craig@sbc-85.com> <= br>Sent: Friday, September 09, 2022 11:08 PM
To: john@jjwhi= tney.com
Subject: Re: SBC-85 plus new project board

=

 

Oh.  I was sort of hoping that was the problem.  I don=E2=80= =99t think the 8251 could keep up with the 6 mhz 8085 but the 8251A should b= e fine.

 

I will keep digging. Let me know if you w= ant to send me one of the duds to look at.  

<= p class=3D"MsoNormal"> 

If I had only one piece of test equipment, it would be my saleae logic anal= yzer. 

 

Did you check the reset line? I thoug= ht that every v2.0 board had it connected but I watched my SPIO video and th= ere I mentioned the first v2 CPU boards did not use the reset.  I don=E2= =80=99t know if that is correct or not but it is worth checking. In the user= s manual, it says that connected with the very first version 2.0 so it is un= likely to be the problem. 

 

Let me know if yo= u come up with any additional insight.

I need to clean the intellec 8 system off my bench and make room t= o make a SBC-85 cpu and solve this problem or at least come up with some goo= d diagnostic tests.

&nb= sp;

Regards

<= div>

Craig



On Sep 9, 2= 022, at 7:49 PM, john@jjwhitney.com wrote:

=

=EF=BB=BF

Hi Craig:

 

     I had the chance to try the SPIO board today and= can not get the serial port to work. The other ports work as expected but I= get no response from the 8251 when I send data to it. I used the confidence= test to send data to the port and the response back was all zeros where you= r documents show different responses. When I do an input to the control regi= ster of the 8251 I get only zeros back. I tried two different boards and 3 d= ifferent 8251 chips with the same results each time.

 

   = ;  I do not know what to try next. Any suggestions?

 

Jack

 

From: craig@sbc-85.com <craig@sbc-85.com>
S= ent: Wednesday, September 07, 2022 6:28 PM
To: john@jjwhitney.com
Subject: RE: SBC-85 p= lus new project board

 = ;

Hi Jack,

I see another tindie order including the SPIO.    A= re you still having trouble getting those going properly? Maybe I need to ta= ke some time to look into it and see what could be going wrong?  if you= are having troubles, let me know what you are seeing and maybe I can figure= out what is going on.

 

regards

&nb= sp;

craig

 

From: john@jjwhitney.com <john@jjwhitney.com>
Sent: Sund= ay, August 7, 2022 1:14 PM
To: craig@sbc-85.com
Subject: RE: SBC-85 plus new project board

 

Hi Craig:

 

       Glad to h= ear you are back at it. I never got the original bus monitor to work 100%, h= ad trouble with the single stepping, so I decided to try the new version of t= he board. I really like the idea of having a front panel with flashing LEDs.= I retired last month and will be looking for things to keep busy and buildi= ng boards is something I enjoy, at least as long as I can see up close.

 

     I never got the serial port to work. I think it h= ad to do with hand shaking, I gave it some thought and when I try again I wi= ll tie CTS & RTS together on both ends and see if that works. I haven=E2= =80=99t look at the code in maybe two years so it will take me some time to g= et back into it and know what I=E2=80=99m doing.

 

   &nb= sp; If you have an extra STD-bus board I can take a look and see what I can d= o with it. I have no experience with that interface so the board would be op= erated in stand alone configuration. I watched the video you sent and will h= ave to look up the project to get additional info. Thanks for the offer and I= hope I can help with the project. Let me know if I can help down the road.<= o:p>

 

Jack

 

From: = craig@sbc-85.com <craig@sbc-85.co= m>
Sent: Sunday, August 07, 2022 12:58 PM
To: john@jjwhitney.com
Subject: SBC-85 plus new project board

 

Hi Jack, I see you got anot= her bus monitor board from tindie.

&nbs= p;

Did we finish up this discussion / p= roblem on the SPIO board or did I drop off the edge of the earth?  I am= trying to remember last august---since august can be good flying weather, s= ometimes when I come back from a long trip, I totally forget where I was

 

If you would use it, I can send you one of the new STD-85 boards I just fi= nished.  it is STD-bus but it has a few fun features and I could always= use your help finding problems with the board / software / documentation.

 

= {93} STD Bus 8085 Single Board Computer First Round of Testing--Getting to k= now the STD-85 - YouTube

 

if you need another project, I can toss it= into the envelope.  Or, if  you are looking for a real change of p= ace, I think I have one of my F8 boards left I could send.

 

let me know

 

best regards,

 

=

craig

 

From: john@jjwhitney.com <john@jjwhitney.com>
Sent: Sunday, August 8, 202= 1 5:31 AM
To: 'craig Andrews' <craig.andrews@tessol-inc.com>
Subject: RE: S= BC-88

 

=

Hi Craig:

 =

     My most recen= t projects include a Z80 CP/M system based on the RC2014 platform as well as= the Glitch works 8085 CP/M system. I just got the Z80 working this weekend a= nd finding a lot of cool stuff from the 1980=E2=80=99s again. The storage sy= stem is a 64MB compact flash drive and the 100 pin bus has many different ca= rds to add to it. The Glitch works 8085 is a bit more limited but has some e= xpansion capabilities. Over all I think your bus structure is better and if y= ou have thoughts of adding a compact flash card for storage they are fairly e= asy to implement. Only problem is the fine pitch surface mount card holder. <= o:p>

 

     One other project is I am trying, yet again, t= o grow Bonsai trees. It is a fascinating hobby but very challenging to start= a tree from a seed and have it grow to a sustainable size. I have had succe= ss in germinating a few trees only to have them all die at some point, some l= asting many months but all seem to succumb to neglect. Maybe as I get in to r= etirement I will have more time to pay attention to them.

 

  &= nbsp;  As for the needed corrections, I still could not get the 8251 on= the SP/IO board to work. Might have something to do with CTS/RTS signals bu= t I=E2=80=99m not sure. I am looking forward to reviewing you future project= s so please let me help when you need a second pair of eyes. Stay healthy an= d productive and I look forward to hearing from you soon.

 

Jack Whitney<= o:p>

 

From: craig Andrews <craig.andrews@tessol-inc.com>
Sent: W= ednesday, August 04, 2021 11:48 PM
To: john@jjwhitney.com
Subject: Re: SBC-88

 

Hi Jack, it is good to hear from you.  I am slowly getting ba= ck into things but have not been working on electronics much.  For some= reason starting (and then finishing) projects seem like a major hurdle.

 

If you have come across any things in the documentat= ion that I need to address, please let me know.  Those are little proje= cts that are easy for me to get traction. 

 

I c= annot remember if I caught up on all corrections on the hardware like the da= ngling ground you found on the serial port.  So let me know if you are s= eeing any hardware problems too.  

 

If you ar= e looking for software projects, the version of tiny basic on the sbc-85 sit= e is still incomplete.

 = ;

yes, there is a lot of goo= d, clean fun left in the 8085 still yet.

 

What proj= ects are you up to?

 

Regards

<= div>

 

Craig

 

<= p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt">On Aug 4, 2021, at 7:02= PM, john@jjwhitney.com wrote:

=EF=BB=BF

Hi Craig:

 =

     Long time since we last c= onnected. So glad you are better now and wish you the best moving forward. I= was a bit worried since you went from a prolific poster to nothing so sudde= nly. Sorry to hear about you contacting Covid-19, I hope you are fully recov= ered or close to it. I know I asked about the 8088 system before but now I=E2= =80=99m hooked on the 8085 and built a few different versions and having a l= ot of fun. Thanks for sending me down that road as I have learned a lot alon= g the way.

 

     Take care and keep me informed of y= our next project. I wish you all the best.

 

Jack Whitney

<= p class=3D"MsoNormal"> 

From: craig.andrew= s@tessol-inc.com <cra= ig.andrews@tessol-inc.com>
Sent: Friday, September 11, 202= 0 7:43 PM
To: john@jjwhitney= .com
Subject: RE: SBC-88

 

Just discovered ther= e is a mistake in the SBC-85 v2

 <= o:p>

Pin 5 of the DB9 was left floating, tha= t needs to be taken to ground

 

Regards

 

Craig

 

 =

From: john@jjwhitney.com <john@jjwhitney.com>
Sent: Sunday, August 23, 2020 6:51= AM
To: guus.assmann@wo= lmail.nl
Cc: c= raig.andrews@tessol-inc.com
Subject: RE: SBC-88

=

 

Hi Guus:

 

     I was able to look at the items yo= u sent. As for the buss structure I believe it will work as described. The o= nly change would be to change the TRAP pin to NMI and connect the NMI pin to= it. Both have the same function on their respective CPU=E2=80=99s, just the= naming difference.

 

     I downloaded the KiCad pro= gram and am working on a new schematic for the 8088 circuit. It will take me= a while as I have to learn how the program works and how to make it all loo= k good.

 

     As for the circuit, I am not a fan of u= sing a Mega chip in support of the design. Reason is simple, I am more of an= old school design type. With the expansion capability of the SBC-85 bus des= ign I see the possibility of recreating an IBM clone type of system if someo= ne so desires. As with any old time CPU design the question of why comes to m= ind and I say because there is a lot to learn from the old stuff and it is f= ar more simple to build than any new concept.

 

    = Give me a few days to discover the KiCad program and I will try to get the C= PU schematic design done. =46rom there I will look into a circuit board desi= gn as well. I am a fan of using four layer PC boards even though they are mo= re expensive to build. I like the grounding effects the internal layers prov= ide and not having to route the power and ground lines helps keep the number= of feed through holes to a minimum. Please keep in mind that these are my p= references and not an absolute for or against any other design. By using a c= ommon bus it is possible for the universe of potential designs to coexist an= d the use of various expansion boards to be built. Keep in touch and thanks f= or the input.

 

Jack

 

From: guus.assmann@wolmail.nl <guus.assmann@wolmail.nl>
Sent: Saturd= ay, August 22, 2020 1:46 PM
To: john@jjwhitney.com
Cc: craig.andrews@tessol-inc.com
Subject: RE: SBC-88<= o:p>

 

<= p class=3D"MsoNormal">Hello Jack,

 

Thanks for the= reply.

Great that you're a= lso willing to participate.

I've done quite a bit of PCB routing, so that's not the problem.

However it's always good if someone c= an check the stuff I've done.

I've printed the schematics from KiCad. (It's a free program, so you migh= t want to download it anyway.)

The schematics were taken from a Hackaday project. I'll put those schema= tics in the mail as well.

Fi= rst thing that would help a lot, is if you can compare the two schematics an= d also have a look at the project on Hackaday.

 

Wh= y did I select this?

Well, t= he hackaday project has been tested and has a lot of software.

Using the ISP interface on the Atmel Meg= a is not too complicated.

B= ut of course, one of the Ram's can be replaced bay an Eprom.

=

And for that Hackaday project, there's a P= CB, so I can test that PCB and the one I've made.

=

It has an IIC bus for adding a RTC and an SD-interfac= e.

But I thing the PCB-desi= gn is compattible enough to fit to the SBC-Bus.

Also a lot of RAM and any Eprom content can come from t= he Mega, fetching it from the SD-card. So very flexible.

Still, I/O can be added with the bus. And the R= S232 interface can stay on as well. All parts do fit the PCB. The only thing= I've not put on (yet) is the IIC-expander MCP23017.

This design doesn't need the 8284 clock chip and t= he Mega does the Uart stuff.

 

One more thing I've= done as preparation is make a document on the expansion bus connector. We n= eed to determine the signals and what to add on the bus. The where to add it= should be a bit logical as well. But routing is not always so easy....

Could you also please check the= se two documents. There's something missing still, I've not added all the st= uff.

 

<= /div>

Anyway, think about it.

And please don't hold back on feedback. (It's a= lso ok if you don't like it at all.)

In that case, we'dd have to think of something else.

I started out with a Z80 design, but thi= s 8088 seems much easier as it has most of the 8085 signals available. (And =C3= =8D've ordered the hackaday PCB for a very nice low price. A total of 1= 0 Euro including shipment, so it can be used as a reference design.)

Using the memory expansion card on= the SBC-85 design should also not be very difficult.

<= div>

 

BR/

Guus Assmann

 

Op 22 augustus 2020 om 17:31 schreef john@jjwhitney.com:

=

Hi Guus:

 

     I can not open the files you sent as I do not ha= ve the proper schematic program. That said What I was thinking was a simple 8= 088 circuit with the 8284 clock chip, 62256 32K ram, 27256 eprom with a 74LS= 573 to decode the address bus. An 8251A USART is desired with it all using C= raig=E2=80=99s SBC-85 bus with the extra signals added to accommodate the ex= tra address lines of the 8088. It should all fit on a board about 100mm X 10= 0mm like the SBC-85.

&nbs= p;

   &nbs= p; I believe the V20 chip you use handles both 8085 and 8088 instructions so= that looks like a good possibility. As of today I do not have the board des= ign capabilities and if I did I am not very good at board design. I can revi= ew any schematic if I can get them in a PDF version so I can open it. Overal= l I am not looking for anything more than a hobby edition and having it avai= lable as open source is desirable. Let me know how I can help and it=E2=80=99= s great to meet another enthusiast.

 

Jack

 

<= div style=3D"border:none;border-top:solid windowtext 1.0pt;padding:3.0pt 0in= 0in 0in;border-color:currentColor currentColor">

From: guus.assma= nn@wolmail.nl <guus.assman= n@wolmail.nl>
Sent: Saturday, August 22, 2020 9:57 AM
<= strong>To:= craig.andrews@tess= ol-inc.com; john@jjwhitney.com=
Subje= ct: Re: SBC-88

 

Hello,

&n= bsp;

Have been= bussy.

Sorry f= or not consulting first, so please regard this as a proposal.

=

More information will follow= .

 <= /o:p>

BR/

<= /div>

Guus Assmann

Op 22 augustus 2020 o= m 1:35 schreef craig.andrews= @tessol-inc.com:

Hi Jack and Guus

 

By way of introduction, you have both expressed intere= st in developing an 8088 version to the SBC-8x ecosystem.  Guus has sta= rted the development of a Z80 version so I have sent him the 8085 CPU board k= icad files as a starting point, I can also send these to you Jack.  Sin= ce I have no plans to create an 8088 CPU it would be fantastic if you two wa= nted to work together on this.  I suspect that if you create a hackaday= project you could find others to join since I have been asked many times if= I am planning an 8088, Z80, and 6502 versions, or if you prefer I can creat= e the hackaday project and you can join as team members.  The short ans= wer is that I am not planning on developing any other CPU board but strongly= encourage others to add to the ecosystem and will support that effort to th= e extent I am able.

 

I look forward to new hardware for the SBC-8x ecosystem and hope this c= omes to fruition.

 

Best regards

 

Craig

 

 

=


 


 

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