Original Altair-Duino Pro ... Console & Utility Port?

[Walt Perko]

Hi, 

I'm wondering since there is only one RS-232 connector on the back of the Original Altair-Duino Pro computers, how is it possible to setup the console on that RS-232 so I can switch between a dumb terminal connected to the RS-232 and switch to a RS-232 to USB adapter tied to my PC/TeraTerm ... and still have a utility RS-232 to control external devices?  

That is, besides the Audio connector on the back of the Original Altair-Duino Pro computer, can I add another RS-232 DE9 connector to the I/O board inside the computer?  Maybe tap the connections to the audio jack?  So far I only need OUTPUT at 9600 BAUD to control the external devices.  IF I only get 5V TTL signals, that would work even better.  

I'm still a little confused that Port 1 is 18d/19d and Port 2 is A6/A7 ... On a normal Altair 8800 Port 0 (the console) = 16d/17d  and  Port 1 (Utility I/O) = 18d,19d.  Right now this seem a little backwards for the Original Altair-Duino Pro computers ... or is Port 0 the SIO?  

Bottom line is, I want the dumb terminal (Geoff VT-100) as my console tied to the DE9 RS-232 port on the back of the Original Altair-Duino Pro computer.  Then I want another RS-232 connector for other external devices.  

(1) Configure SIO             : Primary (USB Programming Port)
(2) Configure ACR             : Not mapped
(3) Configure 2SIO port 1     : Serial (pin 18/19)
(4) Configure 2SIO port 2     : Serial (pin A6/A7)

[Tom Wilson]

Is that the board that has a Bluetooth adapter on it? My original AD (which now lives in a prototype acrylic case) has that setup. I just de-soldered the BT adapter and added a pin header to let me connect a TTL serial adapter.

Between the two serial ports and the USB port, you can run two serial devices and still connect from the PC via USB.

Tom Wilson
wils...@gmail.com
+1(619)940-6311 

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[Walt Perko]

Hi, 

This is the board inside my Altair-Duino Pro v1.5:  

I never added any WiFi ... that's not in the assembly manual I have.  

Which PINs are Tx and Rx for a 2nd RS-232 or 5V TTL (will work perfect) that isn't parallel to the RS-232 tied to the MAX3232 chip?  

IF the Audio jack is Serial OUT, is that 1V P2P or is that a 5V TTL serial OUT?  

.

[Tom Wilson]

OK, you have the terminal board. I actually have one of those in a separate computer project, a CP/M SBC. I just connected my SBC to the GND, TxD, and RxD pins over on the left. Those are connected to the matching pins on the PIC socket.

If you remove the PIC, then you can use those same pins to drive a second serial port, either via an external MAX232 board, or directly via TTL. 

And you can still plug a PC in to the USB port on Arduino for direct PC control. If you don't want the PC to power up the Arduino, get a USB power blocker. They run about $11 for two on Amazon, and they block the 5VDC wire while passing through USB data. That works perfectly to let me run my Pro with the PC on USB, the internal terminal on 18/19, and my Commander X16 on A6/A7.

[Tom Wilson]

Yes, you do... but his prior post didn't ask for the PIC terminal to work. He wanted a PC USB connection, an external serial device, and a dumb terminal.

On Friday, March 28, 2025 at 11:08:00 PM UTC-7 John Galt wrote:

don't you lose the GEOFF terminal functionality with this method of removing the PIC and connecting to the board that way for the second serial port?

[Walt Perko]

Hi, 

I like the idea of pulling the PIC chip since the console will be on an external Geoff terminal with the same PIC.  

I don't need the 3.3V ... I can just use GND, TxD, and RxD on a DE9 connector I can add to the back of the computer.  99.9% of everything I'm planning only needs 9600 BAUD 8N1 OUTPUT from the Altair-Duino Pro computer at 5V TTL levels.  

As I think about this, couldn't I add an "Internal/External Switch" on the back of the Altair-Duino Pro computer going to the power PIN on the PIC rather than pulling the PIC chip?  Just turning the PIC chip OFF/ON?  

.

On Friday, March 28, 2025 at 11:19:28 PM UTC-7 John Galt wrote:

I think he is going to want to keep it, but up to him. 

this is why i prefer the direct soldering to the DUE board itself, to add the second serial, it can be dangerous as you can easily damage the DUE.

your method is good if you do want to replace the GEOFF as the default terminal: thumb up.

[Walt Perko]

Hi, 

IF I can get 5V TTL out, I don't need to convert to RS-232, I might even use a smaller 2 PIN or 3 PIN connector for external connections.  

OTOH, adding another MAX3232 adapter tagging real +5V at a few hundred mA should give me a regular level RS-232 port.  It's basically a level changer chip ... just needs enough amps to go from 5V to +/- 12V at most to 20ma.  

.

On Saturday, March 29, 2025 at 11:07:29 AM UTC-7 John Galt wrote:

i can't speak for the switch turning the pic on and off, but i will say that with all the TTL 232 converters i had major issues with them running at 5V i couldn't figure it out until i switched power to 3.3V then everything started working. no idea, chinese-ium i guess.

[Walt Perko]

Hi, 

Okay, this is my current setup which works well:  

(1) Configure SIO             : Primary (USB Programming Port)
(2) Configure ACR             : Not mapped
(3) Configure 2SIO port 1     : Serial (pin 18/19)
(4) Configure 2SIO port 2     : Serial (pin A6/A7)

Now I want to switch my console to the RS-232 port on the back of the Altair-Duino Pro v1.5 to 9600 BAUD 8N1.  

(1) Configure SIO             : ???

(2) Configure ACR             : Not mapped

(3) Configure 2SIO port 1     : ???
(4) Configure 2SIO port 2     : ???

and do I need to make any other changes in the config files?  

Once I'm satisfied the console is working well, then I can try tapping into the GND, RxD and TxD PINs on the back I/O board.  

.

[Patrick Linstruth]

If he changes SIO to Serial (pin A6/A7), does that mean that port is emulating an SIO and not 2SIO which would require different software?

Is there a way to add one’s own descriptions to the port names, what goes in the parenthesis?

I remember when I was working with the Duino I found using the pin numbers was more confusing than where they actually terminate.

Also, is there any where to download the documentation for the earlier systems?

On Mar 30, 2025, at 1:29 AM, John Galt <furba...@gmail.com> wrote:

you have to change SIO  primary to Serial (pin A6/A7) that is the port on the back of the Altair-duino.

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/ad30cd1e-5ca4-4d2d-981d-ee24ca2967b2n%40googlegroups.com.

[Chris Davis]

Here is the history of the documentation for David's project: https://github.com/dhansel/Altair8800/commits/master/Documentation.pdf

[Patrick Linstruth]

Thanks for that.

I was also trying to find the assembly documentation for the older systems, before the expansion bus was added.

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/22ae535d-d44b-44d2-b9bb-f8f1d4e2614fn%40googlegroups.com.

[Chris Davis]

The assembly instructions for almost all versions can be found here: https://adwaterandstir.com/instructions-by-kit-version/

[Patrick Linstruth]

Ah, if it was a snake it would have bit me. Thanks!

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/751d9570-ee13-4a79-a4d7-206e36e610d7n%40googlegroups.com.

[Walt Perko]

Hi, 

What would be nice is something like this to help make it easier to understand how best to configure an Altair-Duino Pro computer:  

1st Serial I/O Port =  A6/A7   equivalent to a real Altair 8800 address ??d/??d  = Console

2nd Serial I/O Port = 18d/19d  equivalent to a real Altair 8800 address ??d/??d  = 

3rd Serial I/O Port = 

4th Serial I/O Port = 

That's the first thing people need a clear idea of with the Altair-Duino Pro computer.   Then as they add an expansion buss the list would continue:  

1st Serial I/O Port =  A6/A7   equivalent to a real Altair 8800 address ??d/??d  = Console

2nd Serial I/O Port = 18d/19d  equivalent to a real Altair 8800 address ??d/??d  = 

3rd Serial I/O Port = 

4th Serial I/O Port = 

Expansion Buss Board Addresses:  

...

...

...

...

...

...

.

On Sunday, March 30, 2025 at 10:24:08 AM UTC-7 John Galt wrote:

keep in mind when your remapping the serial ports its like the old way of connecting a phone call, your flipping jumper wires around 

so if you remap a port the software still sees the same ports no different its just on the hardware side something else has been connected in the place of the original.

[Walt Perko]

Hi, 

Okay, so what you are saying is I need to tap the Rx and Tx PINs on the PIC chip to get a parallel I/O to a connector to tie into an external terminal for the console.  

I just need to figure out which two PINs are Rx and Tx ... then both the internal and external Geoff terminals should be usable.  I hope the PIC chip doesn't care where the data is coming from, and the other not being used terminal shouldn't care with it's Rx and Tx ... 

.

On Sunday, March 30, 2025 at 5:01:59 PM UTC-7 John Galt wrote:

It is in the 88-2 serial input/output board manual 2sio and 2sio2 manuals.

Together with the configuration menu:

Ports in decimal. 

control register/data register

2SIO port 1 ------  16/17

2SIO port 2   -----  18/19

2SIO2 port 1  ---- 20/21

2SIO2 port 2 ----  22/23

SIO is port 0/1

----

The mapping of all that in the configuration menu is just up to the user. 

"A6/A7" is the 9 pin serial port on the back always.

Serial (pin 18/19) would be the serial port to the Geoff PIC32 on that terminal board.

On the original: 

profile #0 it defaults to using the Programmer micro USB connection as your connection to a primary terminal. putty or teraterm

Profile #1 is set for the GEOFF terminal on Serial (pin 18/19) which is really a fully internal serial device on the PRO kit.

that is all you get with the default pro kit as built by the manual.

I think the original WIFI add on went in place of the Geoff terminal as it shared the pins; I can't remember have to look at the old manual, because you had to map that to use pin (18/19) later i think you could map that in place of (A6/A7) then the rear serial port was disabled as the WIFI was using it. when the Geoff was not used then you needed to Map through the programmers micro usb port.

[Walt Perko]

Hi, 

Here's the original MITS Altair 8800 I/O address list.  

.

On Sunday, March 30, 2025 at 5:01:59 PM UTC-7 John Galt wrote:

It is in the 88-2 serial input/output board manual 2sio and 2sio2 manuals.

Together with the configuration menu:

Ports in decimal. 

control register/data register

2SIO port 1 ------  16/17

2SIO port 2   -----  18/19

2SIO2 port 1  ---- 20/21

2SIO2 port 2 ----  22/23

SIO is port 0/1

----

The mapping of all that in the configuration menu is just up to the user. 

"A6/A7" is the 9 pin serial port on the back always.

Serial (pin 18/19) would be the serial port to the Geoff PIC32 on that terminal board.

On the original: 

profile #0 it defaults to using the Programmer micro USB connection as your connection to a primary terminal. putty or teraterm

Profile #1 is set for the GEOFF terminal on Serial (pin 18/19) which is really a fully internal serial device on the PRO kit.

that is all you get with the default pro kit as built by the manual.

I think the original WIFI add on went in place of the Geoff terminal as it shared the pins; I can't remember have to look at the old manual, because you had to map that to use pin (18/19) later i think you could map that in place of (A6/A7) then the rear serial port was disabled as the WIFI was using it. when the Geoff was not used then you needed to Map through the programmers micro usb port.

On Sunday, March 30, 2025 at 1:51:20 PM UTC-4 r4r...@gmail.com wrote:

[Walt Perko]

Hi, 

I don't have that board that's on page 26 in the 12UpGrade manual.  

My board is the 1.3.1 board:  

.

On Sunday, March 30, 2025 at 5:31:11 PM UTC-7 John Galt wrote:

I didn't, Tom said:

You could tie into the RX and TX on the PIC32 of the Geoff and create an external Serial I/O port

However, that really didn't involve keeping the original Geoff terminal working as he wrote about removing the PIC32 completely to make the connections.

there is also a question as if it would even work keeping the PIC32 in place and attempted to keep its original functionality.

You don't have to go that untested route.

Understand there is a another serial port the RX and TX on the Arudino DUE board itself.

If you remove the LEDS on the DUE for RX and TX then you can solder 2 new wires and create a new serial port which is mapped RX/TX under the configuration menu.

https://www.adwaterandstir.com/wp-content/uploads/2020/09/Altair-Duinov14Upgrade.pdf

go to page 26

[Walt Perko]

Hi, 

When I goto page 26 in that manual I see this:  

.

On Sunday, March 30, 2025 at 9:26:32 PM UTC-7 John Galt wrote:

The board on page 26 is the Arduino DUE, that is the main PCB that has all the pin headers that is plugged into the front panel board with all the Data and address switches and the LEDS.

[Walt Perko]

Hi,  

That board is not in my Altair-Duino Pro computer.  

.

On Sunday, March 30, 2025 at 10:23:46 PM UTC-7 John Galt wrote:

yup that is the correct picture.

[Chris Davis]

> That board is not in my Altair-Duino Pro computer.  

That board is the Arduino Due.  It makes more sense if you start reading on page 24 of the manual that John linked.

[Walt Perko]

Hi, 

I miss-read John's post.  I didn't recognize the one end of the Arduino DUE board ... I thought it was an older version of the I/O board.  

Although I have a few spare Arduino DUE boards, I'm not comfortable with modifying the board.  

For the way the Altair-Duino Pro software is setup, I don't see me trying to make the console anything else now.  I'd rather keep the computer hardware "original".  It's just easier to do stuff with a real S-100 computer and not that much more expensive ... like my Altair 8800c computer.  

.

[Walt Perko]

Hi, 

So now I want to use the USB port to my PC so I can transfer some files ... but I'm not seeing anything ??? 

My setup:  

(1) Configure SIO             : Primary (USB Programming Port)
(2) Configure ACR             : Not mapped
(3) Configure 2SIO port 1     : Serial (pin 18/19)
(4) Configure 2SIO port 2     : Serial (pin A6/A7)

(5) Configure 2nd 2SIO port 1 : Not mapped
(6) Configure 2nd 2SIO port 2 : Not mapped

IF I turn on TeraTerm, shouldn't I see something on the screen at 115,200 BAUD?  When I set TeraTerm to the COM port of the USB cable I get "Cannot open COM12, Not found."  ???  

I tried the "RESET" to original Defaults ... Although I see COM12 in the Windows Device Manager and the Altair-Duino Pro is turned ON and connected ... this seems nuts.  

Geeze, it's bee a few years since I was playing with the Altair-Duino Pro ... 

.

[Walt Perko]

Hi, 

Okay, got a partial fix ... after ReBOOTing my Windows 11 PC, I can now connect to the USB cable from the Altair-Duino Pro on COM12 ...  

Tomorrow, I need to solve the console connection to my PC so I can transfer programs into the  Altair-Duino Pro. 

.

[Gwen Patton]

I use a fork of PuTTY called ExtraPuTTY as the terminal program and transfer program. It contains a very nice version of XModem built in, so all you need do is use the terminal to find what you want to transfer or where you want to put something from the computer you're using to access it, then activate the XModern feature and the file is losslessly transferred. I now use ExtraPuTTY, for all retro computers I use. It's no harder than regular PuTTY, and it saves steps because the file transport is in the same program as the terminal.

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/ea0eaff7-7383-4946-bde4-76edf833208dn%40googlegroups.com.

[Patrick Linstruth]

Walt, when something isn’t working, rebooting Windows should always be the first trouble-shooting item on the list.

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/ea0eaff7-7383-4946-bde4-76edf833208dn%40googlegroups.com.

[Walt Perko]

Hi, 

I use TeraTerm ... I can open as many instances of TeraTerm as I need for testing stuff.  Right now I'm trying to get the console back on the USB cable instead of the VGA port.  

.

[Walt Perko]

Hi, 

Yeah, I like that TV series ... too bad it didn't go longer.  The last few episodes they even had a real Altair 8800 on the shelf for a background prop.  

.

[Chris Davis]

It's not only a real Altair, it's also the third Altair ever made.

[Walt Perko]

Hi, 

Yeah, I have PING:  

200 REM write to serial port
205 PRINT"PORTS TO TEST: 18,20,22"
206 PRINT"ENTER A PORT TO TEST IN DECIMAL"
207 INPUT PORT
210 PN=PORT
220 A$="THIS IS A TEST. 0123456789 ABCDEFGHIJKLMNOPQRSTUVWXYZ"
225 A$=A$+CHR$(13)+CHR$(10)
230 A=INP(PN) : REM read from control register
240 FOR I=1 TO LEN(A$)
250 IF A AND 2=0 THEN 250 : REM bit 1=0 when output register is full
260 OUT PN+1,ASC(MID$(A$,I)) : REM send test byte
270 NEXT
280 END

But as I have been learning MBASIC I think I wrote a different test program with the help from PatrickL.:  

10 REM OUTPUT ALPHA DATA TO SERIAL PORT X  SEROUTXX.BAS.txt
20 INPUT "What is the PORT Ctrl Address";PCTRL
30 INPUT "What is the PORT DATA Address";PDAT
40 INPUT "Auto Send DATA or Type IN Data";ST$
50 IF ST$ = "S" THEN GOSUB 1000
60 IF ST$ = "T" THEN GOSUB 2000
999 END
1000 REM Auto Send DATA to the Serial Port
1010 FOR X = 65 TO 127
1020 PRINT X
1030 OUT PDAT,X
1040 NEXT X
1050 GOTO 1000

2000 REM Typing DATA OUT the Port
2010 INPUT$(X)
2020 GOTO 2010

Then from Patrick's 6850 initialization, Tom's Dumb Terminal, I have made a few improvements which should work with all 88-2SIO and probably 88-SIO boards.  

0 REM TOM WILSON DUMB TERMINAL ENHANCED by Walt Perko  DUMBTERM.BAS.txt

100 REM RESET AND INITIALIZE 2SIO 6850
110 INPUT "WANT LOOPBACK TYPE L";LB$
120 INPUT "CTL PORT ADDRESS ";CTL
130 OUT CTL,3
140 OUT CTL,21

150 GOSUB 300
160 GOSUB 400
170 GOTO 150

300 REM SEND KEYBOARD INPUT
310 A$=INKEY$
320 IF A$="" THEN RETURN
330 OUT CTL+1,ASC(A$)
340 RETURN

400 REM RECEIVE AND PRINT INPUT
410 IF (INP(CTL) AND 1)=0 THEN RETURN
420 C=INP(CTL+1)
430 PRINT CHR$(C);
440 IF LB$="L" THEN OUT CTL+1,C
450 RETURN

9999 END

.

On Thursday, April 3, 2025 at 9:15:34 AM UTC-7 John Galt wrote:

I use Teraterm i like it better then putty or extraputty.

the defaults for the connection is usually 9600,8N1

unless you really did set your baud rates that high to 115,200

its somewhat confusing because there are a few places you need to set your baud rates.

The Pro board with the GEOFF has its own port management first thing i would do is Control F12 with the Geoff terminal and make sure you have the RS232 settings correct in there. 9600,8N1 

after that you want to go into the configuration menu and if remember under E and S you want to make sure all the settings match up with each other.

one that is done and you have your USB to your windows 11 machine and Teraterm is running and making a connection...

here is where an anomaly comes in that i noticed: i can only say this happens with windows machines and teraterm....

teraterm for some reason will not complete the initial connection until it sees something come into the port that it picks up.

so i wrote a little program called "PING" i actually sent you this program a few years ago in our email exchanges.

its a little MBASIC program which i compiled and put into the Root of the A: for Cp/M to see for all users.

Ping asks you which port you want to send out a ABC alphabet test string to. 

first it asks what port you want to ping in decimal 18 is usually the 9 pin serial port on the back of your altair-pro machine. 20,22 are the 2SIO2 ports that are higher and require a Firmware recompile to enable.

once you select 18 it will then send out the ABC test string on that port. tera term will then see the test string and complete the connection.

Now you want to use the mini usb port for your connection and leave the 9 pin serial alone on its own. 

so you have to be careful how you map them for file transfer without modifications. to use the standard pcput and pcget it can only see 2SIO port 1 and port 2 that is 16/17,18/19 in decimal.

16/17 is in use with the disk drives and the primary terminal so you only have 18/19 to play with... in the configuration menu you would need to change your port mapping from the A6/A7 to USB programming for 2sio port 2 in order to have a file transfer connection.

you would then use PING in the same way so that teraterm completes the connection over USB.

now on my setup i have added USB native on the back of my case, so i have 2 micro USB connectors easy modification. i have also modified the altair firmware to enable 2sio2 ports 1 and 2

i then map 2sio2 port 1 to my USB Native.

the USB then goes from native into my windows 10/11 machine.

i establish a connection via teraterm.

then i run PING on the altair in cp/m to port 20.

that sends out the ABC test string and teraterm completes the connection. 

i have modified PCPUT AND PCGET into PCPUT2 and PCGET2 these new versions only talk to 2sio2 where the original only talks to 2sio. 

now i can send and receive my files from my windows to altair machine on this higher serial port using Xmodem.

this leaves all my lower port mapping alone i never have to change them.

otherwise because you only have one usable 2sio port 2 serial port then your stuck going into your configuration menu and changing around your port mapping.

with one available port 

then you would the command

PCPUT WALT.BAS B   to send to your windows 11 machine

or

PCGET WALT.BAS B to receive from your windows 11 machine.

The "B" is super important because you have to be mapped to only open port you have that PCGET and PCPUT can see without modifications.

if you have a serial port ABCD switch then you can really play around with devices you have connected.

thing to remember is teraterm will see the port and make the initial connection but it won't finalize it until it sees activity coming in. it kind of sits there in a waiting loop and then Xmodem will not transfer just sits there waiting.

also you have to make sure you have mapped the port such that your communications software under Cp/M can see it and talk to it this is limited without modification.

just about all the standard communications programs will only see 2SIO PORT 1 or 2 and that means you need to switch around your ports in the configuration menu.

 

since you have a stock setup then make sure you remap 2SIO port 2 from A6/A7 to USB programming.

all of this sounds complex and overwhelming but it isn't you just have to understand why your shifting things around in the first place.

[Walt Perko]

Hi, 

After more fiddling with the computer I now have two good working systems on Altair-Duino Pro USB and the Altair-Duino Pro Back Panel Keyboard & VGA.  

Both setups have all the same favorite drives and ZPU.  

It's incredible how some of that stuff got lost in my brain and then today, much of it comes back and I get the Altair-Duino Pro configured better than before when I quit to get real Altair 8800 experience.  

The only thing I don't like about the real Altair 8800 experience is the troubleshooting boards when they're not working ... but with good working boards, I think it's a more rewarding experience.  

As for software, the two seem to be about the same with MBASIC and .COM programs.  

HAPPY - HAPPY - HAPPY - AGAIN!  

.

On Thursday, April 3, 2025 at 12:00:11 PM UTC-7 John Galt wrote:

i good handshake message could be "CONNECT [BAUD RATE]"  just like the old modem days. that would trigger teraterm and off you go.

On Thursday, April 3, 2025 at 2:58:06 PM UTC-4 John Galt wrote:

Whatever you use. 

When you establish a connection with teraterm, send it a some characters.

If you see them on the teraterm terminal then you have established a connection.

from there you use any communications software you like and you can send in any format you wish X,Y,Z modem transfers back and forth.

just remember most cp/m communications software was only designed to see the first SIO card and its ports, so make sure you have your ports mapped as you need them in the configuration menu.