Can't Read µSD Card?

[Walt Perko]

Hi, 

When I do a "D" to load 330KB .dsk's nothing happens when I type any of the numbers ??? 

You can see it happening in this video.  

.

[Walt Perko]

Hi, 

I forgot to add ... am I right?  Is the problem the computer is not reading the µSD card now?  

.

[Tom Wilson]

Try using (M)anage Filesystem to see if the system is reading the card.

[Walt Perko]

Hi, 

Okay, this is what I get ... doesn't look like what the book says:  

ID Type            Name        Size
-----------------------------------
00 Configuration   #05           99
01 Configuration   #09           99
02 Configuration   #00           99

Filesystem size: 16384 bytes
         in use: 325 bytes
      available: 16059 bytes


Command (dFrx):

Read file with id: 00
0000: 01 00 00 0A 98 3D 23 00  77 E0 77 00 18 63 8C 01   .....=#. w.w..c..

ID Type            Name        Size
-----------------------------------
00 Configuration   #05           99
01 Configuration   #09           99
02 Configuration   #00           99

Filesystem size: 16384 bytes
         in use: 325 bytes
      available: 16059 bytes


Command (dFrx):

Read file with id: 01
0000: 01 00 00 0A 98 3D 23 00  7B E0 77 00 18 63 8C 01   .....=#. {.w..c..

ID Type            Name        Size
-----------------------------------
00 Configuration   #05           99
01 Configuration   #09           99
02 Configuration   #00           99

Filesystem size: 16384 bytes
         in use: 325 bytes
      available: 16059 bytes


Command (dFrx):

Read file with id: 02
0000: 01 00 00 0A 98 3D 23 00  77 E0 77 00 18 63 8C 01   .....=#. w.w..c..

.

[Chris Davis]

The SD card is not recognized.  If it was you would see "(F)ile System Manager for SD Card" on the configuration screen.

[Walt Perko]

Hi, 

Okay ... Now I see ... so I guess I need to see if there's a cold solder joint or the µSD Card slot has gone bad.  This is a computer I bought used:  

Enable pro(f)iling          : no
Set throttle delay (t/T)    : auto adjust
Enable serial (p)anel       : no
Enable serial (i)nput       : no
Enable serial (d)ebug       : no
Configure (m)emory          : 64 KB RAM, 0 ROMs
Pro(c)essor                 : Zilog Z80
Aux1 shortcut program (u/U) : 16k ROM Basic
Configure host (s)erial     : Primary: USB Programming Port

(E) Configure serial cards  : SIO,2SIO-P1 mapped
(D) Configure disk drives   : 0 mounted
(H) Configure hard disks    : 0 mounted
(V) Configure VDM-1         : On USB Native Port
(I) Configure interrupts    : Interrupts connected directly to CPU

(M)anage Filesystem     xxxxx MISSING! xxxxx
(S)ave configuration    (L)oad configuration
(R)eset to defaults     E(x)it

Command:

On the computer that is working (DAZZLER SetUp):  

Enable pro(f)iling          : no
Set throttle delay (t/T)    : auto adjust
Enable serial (p)anel       : no
Enable serial (i)nput       : no
Enable serial (d)ebug       : no
Configure (m)emory          : 64 KB RAM, 0 ROMs
Pro(c)essor                 : Zilog Z80
Aux1 shortcut program (u/U) : 16k ROM Basic
Configure host (s)erial     : Primary: USB Programming Port

(E) Configure serial cards  : SIO,2SIO-P1,2SIO-P2 mapped
(P) Configure printer       : None
(D) Configure disk drives   : 4 mounted
(H) Configure hard disks    : 4 mounted
(Z) Configure Dazzler       : On USB Native Port
(I) Configure interrupts    : Interrupts connected directly to CPU

(M)anage Filesystem     (F)ile manager for SD card
(S)ave configuration    (L)oad configuration
(R)eset to defaults     E(x)it

Command:

SD card file manager

(d)irectory
(t)ype out file
(D)ump file
(r)eceive file via XMODEM
(s)end file via XMODEM
(c)opy file
(R)ename file
(e)rase file
(h)elp
E(x)it

Command:

Command: d
STORAGE .DAT     512K     STORAGE0.DAT     512K     STORAGE1.DAT     512K     STORAGE2.DAT     512K     STORAG~1.DAT     512K     BOBA-D~1.DSK    8768K     CDISK01 .DSK     250K     CDISK02 .DSK     611K     CDISK03 .DSK    1227K     DISK01  .DSK     330K     

DISK02  .DSK     330K     DISK03  .DSK     330K     DISK04  .DSK     330K     DISK05  .DSK     330K     DISK06  .DSK     330K     DISK07  .DSK     330K     DISK08  .DSK     330K     DISK09  .DSK     330K     DISK0A  .DSK     330K     DISK0B  .DSK     330K     

DISK0C  .DSK      75K     DISK0D  .DSK      75K     DISK0E  .DSK      75K     DISK0F  .DSK      75K     DISK10  .DSK     330K     DISK10~1.DSK     330K     DISK11  .DSK     330K     DISK12  .DSK     330K     DISK13  .DSK     330K     DISK14  .DSK      75K     

DISK15  .DSK     330K     DISK16  .DSK     330K     DISK17  .DSK     330K     DISK18  .DSK     330K     DISK19  .DSK     330K     DISK19~1.DSK     330K     DISK1A  .DSK     330K     DISK1B  .DSK     330K     DISK1C  .DSK        0     DISK29-1.DSK     330K     

DISK29  .DSK     330K     DISK29~1.DSK     330K     DISK29~2.DSK     330K     DISK30  .DSK     330K     DISK30~1.DSK     330K     DISK31  .DSK    8768K     DISK31~1.DSK    8768K     DISK32  .DSK    8768K     DISK32~1.DSK    8768K     DISK33  .DSK     330K     

DISK33~1.DSK     330K     DISK34~1.DSK     330K     
HDSK01  .DSK    4872K     HDSK02  .DSK    4872K     HDSK03  .DSK    4872K     HDSK04  .DSK    4872K     HDSK04~1.DSK    4872K     HDSK05~1.DSK    4872K     HDSK06~1.DSK    4872K     HDSK07~1.DSK    4872K     HDSK20  .DSK    4872K     HDSK20~1.DSK    4872K     

HDSK21  .DSK    4872K     HDSK21~1.DSK    4872K     HDSK22~1.DSK    8768K     HDSK23~1.DSK    4872K     JGDAZZ~1.DSK     330K
TDISK01 .DSK     250K     TDISK02 .DSK     250K     TDISK03 .DSK     250K     TDISK04 .DSK     250K     TDISK05 .DSK     250K     TDISK06 .DSK     250K     WKP00D  .DSK      75K     Z-BLAN~1.DSK    8768K     Z-CPM2~1.DSK    8768K     
CDISKDIR.TXT      388     DISKDIR .TXT     1303     DISKDI~1.TXT     1239     FILELIST.TXT     1003     HDSKDIR .TXT      481     HDSKDIR0.TXT      482     HDSKDI~1.TXT      481     README  .TXT     1712     TDISKDIR.TXT      461

Command:

.

[Walt Perko]

Hi, 

Okay, I looked at the solder points on the µSD Card Slot ... they look okay, the soldering job is blobby ... 

     

but I touched each with my solder pen to be sure the solder flowed nicely.  

ReAssembled the connections, but still the computer is NOT seeing the µSD Card ... 

I need a part number (link?) to get a replacement µSD Card slot.  I hope I can remove the existing one, but my eyes are not as good as they were 3-4 years ago.  

.

[David Williams]

Before I tried another slot, I'd try a different card. Sometimes they go bad, or a particular card may not be fully compatible.

[Walt Perko]

Hi, 

By now, I've tried four different 128MB µSD cards ... they all have the same problem.  

.

[Flavio Villanustre]

Check for conductivity with a tester. Sometimes a trace gets damaged by heat or other factors.

I hope this helps.

Flavio

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[David Williams]

Checking connectivity is a good idea. Be sure to check it all the way back to the Arduino, not just to the PCB.

[Chris Davis]

See if the guy missed adding the six-pin header under the Arduino.  90% of the time guys email me about the SD card not working, it's because they missed that header.

As far as the part number of the SD module, it doesn't have one.  Just look up SD modules on Amazon and you'll find it.

[Walt Perko]

Hi, 

It was working for me for a couple of years now, but when I went to add some .DSK files, now it doesn't connect inside the µSD card slot.  It only fits one way, the same as on my other computer which can read the µSD cards so I'm sure it's the slot that has gone bad.  

Yes, I should double check full continuity from the solder points to the board.  

.

[Walt Perko]

Hi, 

I pulled the board out of the computer to touch onto each solder point of the connector top/bottom, I also did check for anything inside the slot, but it's clean, the card just doesn't seem to make contact inside the slot.  

I just finished cleaning the area up with 100% alcohol and double-checking continuity from the PINs on the connector to various PINs on the board and it looks good there too.  

I have noticed that the DUE doesn't seem to react the same in this machine as the DUE in the other computer I built.  STOP + AUX1 UP doesn't always work unless I pull the USB power and restart it again.  

.

On Thursday, May 8, 2025 at 12:25:18 PM UTC-7 John Galt wrote:

if you can shine a light down into the empty SD slot see if you spot something broke off inside from an earlier SD card, or if the contacts look wrong.

I once had a piece of a micro SD crack off and it was left inside the slot. when i inserted another micro sd the broken piece went to the bottom against the shield.

the new SD felt fine when it went in and seemed to be seated all the way but nothing would work.

i would take the same micro SD to another slot and it worked fine but then refused to work in the other.

that was when i shined a light inside the micro SD slot and i kept looking at it. then noticed a little piece of black plastic wedged inside. i went to look at all my micro SDs with some magnifiers on and that was when i noticed one SD had a little piece broken off.

i had to get creative with a set of micro picks, but i got the plastic out and confirmed it came from the chip off the micro SD then the reader worked properly again.

[David Williams]

I'd take a look at the connectors for the Due, and maybe try swapping a different Due in.

[Walt Perko]

Hi, 

For starters, I'm NOT a c programmer, I've only used Arduino stuff that is in products, I have near zero experience with Arduino.  I can write very basic MBASIC programs.  I am getting pretty good writing DAZZLER programs with Bob Ammerman's DZMBASIC.  

Okay, I'm on this page:  https://adwaterandstir.com/install/  ... I got this document:  Documentation.pdf, reading instructions on page 18, so then I downloaded the https://github.com/dhansel/Altair8800, then I edited the config.h to add the "1" to enable VDM-1 from the  https://github.com/dhansel/VDM1

I did all the Arduino updates for my Windows 11 PC ... 

I got past the DueFlasStorage, and I see some SparkFun libraries, but nothing ... how do I find the SparkFun SD Library?  Is it the library called:  SparkFun SD30?  

Click Sketch > Include Library > Manage Libraries... In the search box, enter "DueFlashStorage", select the library, and click Install. Search for the SD library (by SparkFun) and install version 1.1.1 (the default version has a problem with the Altair-Duino).

BTW, old eyes find it difficult to read the light grey text 

The .bin to upload into the DUE was quick 'n easy.  Why can't there be a .bin with VDM-1 enabled?  Same for the DAZZLER ... and IF both can fit, why not have them both enabled in yet another .bin file with simple string to run in the CMD screen to get a new DUE up 'n running?  

I guess there might be other configurations that also could use a simple .bin to make this process easier.  

The next stump is I cannot find and AppData in either my C:\Users\wperko  or  C:\Users\Public ??? 

You will want to switch the Arduino compiler's optimization setting to "performance". You can find this setting in c:\Users\user]\AppData\Local\Arduino15\packages\arduino\hardware \sam\1.6.9\platform.txt (Your version "1.6.9" may be different.) Edit this in a text editor and change any occurrence of "-Os" to "-O3". If you skip this step the simulator will still run but it will run significantly slower, and some of the expansion cards will not work.

Not finding that I did do the UpLoad to the DUE and did not get any errors.  

.

[Walt Perko]

Hi, 

Okay, got the brand new DUE installed and it doesn't even get started as an Altair 8800 ??? 

Is it the instructions don't seem to be up to 2025 Windows 11 ... I don't know how to get the DUE programmed for the VDM-1 ???  

.

[Walt Perko]

Hi, 

I did the original .bin upload and the new DUE is working except that it cannot access the µSD card ...  

I'm pretty sure I need a new µSD card reader as the card is not making a connection to the slot.  

Does anybody have the proper part number or a link for buying a new µSD card reader?  

.

[Marco]

I recently bought 10 (the exact same model) from China for a whopping 56 cents each. Order 1 instead of 10 and you pay less than 3 Dollars. It was part of a larger order so I had no shipping costs but even with shipping they're cheap. And just work. Just takes a week or so for delivery.

https://www.aliexpress.us/item/3256805191414679.html?gps-id=pcStoreJustForYou&scm=1007.23125.137358.0&scm_id=1007.23125.137358.0&scm-url=1007.23125.137358.0&pvid=bab35d5a-aa87-40f8-af6c-b5f15960c720&_t=gps-id%3ApcStoreJustForYou%2Cscm-url%3A1007.23125.137358.0%2Cpvid%3Abab35d5a-aa87-40f8-af6c-b5f15960c720%2Ctpp_buckets%3A668%232846%238112%231997&pdp_ext_f=%7B%22order%22%3A%22338%22%2C%22eval%22%3A%221%22%2C%22sceneId%22%3A%2213125%22%7D&pdp_npi=4%40dis%21EUR%212.40%211.94%21%21%212.63%212.13%21%402103917f17467742340633388e84ed%2112000032804713175%21rec%21NL%21%21ABX&spm=a2g0o.store_pc_home.smartJustForYou_2003946192658.1005005377729431&gatewayAdapt=glo2usa4itemAdapt

Op vrijdag 9 mei 2025 om 07:18:29 UTC+2 schreef r4r...@gmail.com:

[Walt Perko]

Hi, 

This makes me wonder if a Serial CP/M couldn't be added to the Altair8800 sim ... then a µSD card wouldn't be needed at all.  

Maybe it takes a newer board with more memory?  IF so, then perhaps it's time for a new design.  

I've got two packages sitting in Long Beach, CA. since March ... I think all the tariff noise has them sitting on hold.  The Aliexpress µSD card modules are now $3 + shipping.  Still a reasonable price, but I don't know if they would actually get to me until the tariff crap ends.  

.

[Chris Davis]

You can get them from eBay (US sellers) or Amazon.

[Walt Perko]

Hi, 

Looks like either of these will work as a replacement µSD card reader:  

https://www.digikey.com/en/products/detail/groundstudio/HBCTZI-AAA/21080894?s=N4IgTCBcDaIKwAYDsAWAtACQEIGEAqAWgJID6AghWgHIAiIAugL5A

https://www.adafruit.com/product/4682

.

[Tom Wilson]

My thinking regarding "Serial CP/M".

Instead of modifying CP/M, what if we modified the emulator itself to add in the functionality similar to Mike Douglas's FDC+? 

If I understand correctly, the FDC+ emulates a floppy disk drive and talks to a  server program running on a PC, rather than using a physical diskette drive. I peeked at the manual last night (when talking to someone else about a different project - a Z80 card for the Commander X16), and this seems like a great way to expand the Altair-duino's storage and allow easy file transfers to/from the PC. 

The only ports on the AD that are reasonably fast enough for this would be the USB ports, and so it would make sense to use the native USB port for this (since it can run at native USB speeds, rather than being limited by the UART in the programming port.)

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

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/27fae25e-47fd-4035-9b78-b115024d61c6n%40googlegroups.com.

[Chris Davis]

I would not use the DigiKey or Adafruit modules linked.  They are not the same as the module used in the Altair-Duino.

[Walt Perko]

Hi, 

I think a Serial CP/M would need to be on another serial port since the Native USB Port is used for DAZZLER and VDM-1 ... 

I don't think there would be a serious problem with using A6/A7 at 19.2K BAUD ... that's plenty fast for loading programs ... only the initial BOOT to CP/M might take a few seconds.  It is still going to be faster than my Windows BOOTs ever was.  

.

[Walt Perko]

Hi, 

On eBay, I only found µSD card reader one that might be compatible and it's in Greece!  

This is why I need either a part number or a link to buy a µSD card reader for the Altair-Duino Pro computer.  

.

[Chris Davis]

Check your search terms.  I found seven of them in the US on eBay.

https://www.ebay.com/sch/i.html?_nkw=sd+card+module&_sacat=0&_from=R40&rt=nc&LH_PrefLoc=1

Also check Amazon, there are at least as many on there.
https://www.amazon.com/s?k=sd+card+module&crid=32H0OFTT9DDSG&sprefix=sd+card+module%2Caps%2C352&ref=nb_sb_noss_1

[Walt Perko]

Hi, 

I guess it's the search nomenclature ... I was searching for micro sd card readers ... getting very different results.  

Thanks for the eBay link ... I bought the 5x for $10.  I may never need the other four, but I can send them to friends as needed.  

.

[Walt Perko]

Hi, 

Something I just realized ... all the PINs from the µSD card connect to the ribbon cable going to the front display panel, but could there be something else on the VT-100 board it connects to also that might be screwing things up?  

I know I've isolated the DUE simply by programming a new DUE and installing that into the computer, but not everything on the front display panel ???  Could there be a chip going bad on the front display panel or does all the µSD card signals just go direct to the DUE?  

.

[Chris Davis]

It's just a direct connection from the SD card module to the SPI connector on the Due.  It should not connect to any other component.

[Walt Perko]

Hi, 

New µSD card reader installed, all connections look good, but still even the NEW Arduino DUE doesn't read the  µSD card ??? 

I can only conclude something has gone wrong on the Altair-Duino Pro Front Panel Display board.   

Any ideas how to move forward finding the problem part?  

Both photos the new µSD card reader on the left ... the old µSD card on the right ... 

          

Enable pro(f)iling          : no
Set throttle delay (t/T)    : auto adjust
Enable serial (p)anel       : no
Enable serial (i)nput       : no
Enable serial (d)ebug       : no
Configure (m)emory          : 64 KB RAM, 0 ROMs
Pro(c)essor                 : Zilog Z80
Aux1 shortcut program (u/U) : 16k ROM Basic
Configure host (s)erial     : Primary: USB Programming Port

(E) Configure serial cards  : SIO,2SIO-P1 mapped

(P) Configure printer       : None

(D) Configure disk drives   : 0 mounted
(H) Configure hard disks    : 0 mounted

(Z) Configure Dazzler       : Disabled

(V) Configure VDM-1         : On USB Native Port
(I) Configure interrupts    : Interrupts connected directly to CPU

(M)anage Filesystem     (?) NO  µSD card  ???  

(S)ave configuration    (L)oad configuration
(R)eset to defaults     E(x)it

Command:

.

[David Williams]

Did you verify the connections all the way back to the Due?

[Walt Perko]

Hi, 

the continuity from the solder PINs on the µSD Card slot to the ribbon cable connector is verified 100% for all PINs.  

It's as if there is an incorrect setting in the Configuration Editor ... 

I really wish the Serial CP/M was built-into the simulator so we could just use the RS-232 serial port on the back of the computer to connect to drives running on a PC.  

.

[udo....@freenet.de]

r4r...@gmail.com schrieb am Samstag, 17. Mai 2025 um 03:54:29 UTC+2:

the continuity from the solder PINs on the µSD Card slot to the ribbon cable connector is verified 100% for all PINs.

Have you measured for any short between the pins? Because that is another usual source of error.

[David Williams]

I'm questioning the connections to the Due itself. If there's a problem there, all these other things won't matter.

[Walt Perko]

Hi, 

Yes, I did continuity tests including looking for a short.  I've replaced the DUE and the µSD card slot ... 

Could something on the I/O board?  

.

On Saturday, May 17, 2025 at 6:16:16 AM UTC-7 udo....@freenet.de wrote:

[Walt Perko]

Hi, 

The DUE just plugs down onto the front panel board ... perhaps a PIN isn't making a connection, but I would expect that to kill off more than just the µSD card.  

It is almost impossible to see inside the computer if everything is connected properly between the DUE and the front panel board ... especially with my aging eyesight.  

.

[Chris Davis]

You need to check continuity from the SD card module to the SPI 2x6 connector on the Arduino Due.

[Walt Perko]

Hi, 

Thanks Chris ... that is good info and I'll give it a test as soon as I can.  

I'll have to pop the plastic guard off the DUE ... I hate doing that, but that seems like the most logical step to take at this time.  

.

[Marco]

Hi,

There is no need for the plastic guard when the DUE is mounted on the Altair-Duino board, I would just remove it permanently. It is handy for when these boards are used lying on the table, not when mounted on a board or in a case.

To check the SD card reader, first check if you have 3.3 volts by probing the GND and 3v3 pins on the SD card reader with a multimeter when the Alair-Duino is switched ON.

Then with the Altair-Duino switched OFF, check continuity from the other pins on the SD card reader to the pins on the DUE. Also check for shorts, i.e. no other pins should make contact. It's the six pins just below the DUE logo:

------------

|  DUE  |

------------

1    2    3

4    5    6

1 = CS

2 = MOSI

3 = not used

4 = not used

5 = CLK

6 = MISO

If all those check out okay, then there should be no reason for the SD card reader not working... Maybe double check if all the pin headers where the DUE is mounted on are soldered correctly, without any solder bridges.

Good luck!

Op zondag 18 mei 2025 om 02:07:35 UTC+2 schreef r4r...@gmail.com:

[Walt Perko]

Hi, 

There is full connectivity from the µSD Card Slot to the 6-PINs on the back of the Arduino DUE.  

So now, it seems it's something in the software in the Arduino DUE.  I've already replaced the Arduino DUE board and continue to have the same fault.  

Another question is, how can I read the program inside the DUE back onto my PC?  

.

[Flavio Villanustre]

This is a shot in the dark, but have you tested to make sure that there are no shorts between the different traces going to the SD card reader socket? A soldering bridge would potentially create such an issue too.

I hope this helps,

Flavio Villanustre

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[Walt Perko]

Hi, 

That question has been answered a few times in this thread already.  There are NO Shorts.  

.

[Marco]

I don't know if you already did, but a good way to troubleshoot a problem is to first start with the absolute basics and then build up from there to find the problem by eliminating the things that do work. I read about VDM-1 board, altering settings in the Arduino config, etc. Which in the end you will want to do, but to first find out why you can't get the SD card reader to work maybe you should exclude as much as possible. 

My suggestion would be to remove all extra's. Download new Arduino source code and flash this to the Arduino unaltered.  Download new SD card content and copy it to the SD card unaltered. I guess you could even remove the expansion board and connect (and power) directly from the USB Programming Port. If that doesn't get the SD card working then there is really something fundamentally wrong with your kit...

Op donderdag 22 mei 2025 om 21:07:54 UTC+2 schreef r4r...@gmail.com:

[Walt Perko]

Hi, 

The computer stopped reading the µSD card which is why I bought a new card slot and installed it.  

Now I've isolated all the components as far as I can.  

I'm not sure how a nice ribbon cable can go bad.  It is still in pristine condition, besides that, all the other signals are getting through to the I/O board.  

     

I've tried three of the Altair8800.bin files from 2021, 2023 and 2025 that I've downloaded from the AdWaterandStir website.  

Now I'm wondering if maybe the 3.3V is missing going to the µSD card.  

The connection to the 3.3V PINs on the I/O board shows continuity, but doesn't that 3.3V also support other items/components on the I/O board?  

.

On Thursday, May 22, 2025 at 2:10:00 PM UTC-7 John Galt wrote:

another long shot would be swapping the ribbon cable if you have the GEOFF setup with SD to rule that out as well.

On Thursday, May 22, 2025 at 5:08:18 PM UTC-4 John Galt wrote:

agree ^

what if the issue is when your changed the firmware and recompiled it you have slightly wrong libraries loaded, i know 4-5 years ago i had a pickle of a time finding all the correct libraries. the code would compile sometimes with the wrong libraries and upload to the due then nothing worked right.

go back to a known working state and start over, at this point the Due and SD seem to be ruled out on the hardware side as a cause since i believe you swapped them between another altair-duino that is already working.

if going back to default firmware does not work then its another to rule out as the issue.

that just has you questioning the front panel or if you have a GEOFF board with the SD on it as a possible issue.

[Patrick Linstruth]

Do you have a scope or logic analyzer? You could see what, if anything, is happening on CS, MISO, MOSI, and CLK. You can also see if the 3.3v is present.

On May 22, 2025, at 6:34 PM, Walt Perko <r4r...@gmail.com> wrote:

Hi, 

The computer stopped reading the µSD card which is why I bought a new card slot and installed it.  

Now I've isolated all the components as far as I can.  

I'm not sure how a nice ribbon cable can go bad.  It is still in pristine condition, besides that, all the other signals are getting through to the I/O board.  

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<UpLoad Binary DUE-01.jpg>

[David Williams]

How about the uSD card image. Did you format it yourself? You might try imaging it with the SD card image downloaded from adwaterandstir.com.

[Walt Perko]

Hi, 

The µSD card has been working just fine for several years, the new card is an exact copy of all the files with no errors, a third µSD card I made from the files I saved when I had gotten the 1st card working back in 2021.  

I'm pretty sure it's not a µSD card issue anymore.  

.

[David Williams]

I'm questioning the partitioning and the formatting. Writing a card image sidesteps those variables.

[Walt Perko]

Hi, 

That test is my next test, but it's difficult as with power ON, my shaky hands and bad eyesight are not so good at tapping a probe down onto the tiny PINs.  I may have to cut off a soda straw and try using that as a guide down onto the 3.3V PIN.  

.

[Walt Perko]

Hi, 

Okay, the 3.3V and GND are on the µSD card slot.  Now when I do a STOP + AUX1 UP this is what I'm getting:  

I think that *=Lamp test might be a new clue ... it comes up each time I do the  STOP + AUX1 UP 

.

[Chris Davis]

Lamp test has nothing to do with the SD card.  It was added to the config menu a couple years ago.

[Walt Perko]

Hi, 

Yeah, that was an older Altair8800.bin file I UpLoaded into the DUE ... 

I almost wish I had a little connector with two or more LEDs that would plug into the µSD card slot to see POWER, Chip Select and maybe another important signal latched on the DATA IN Pin.  

I wish I could get this problem fixed, but I'm lost other than swapping out the front panel display board now.  

.

[Marco]

I think you are (still) over-complicating things, you really need to go to the basics and start over from (almost) scratch. It is my believe that if you don't, you'll never get to the source of your SD card problem...

So, and partly repeating myself, here's what I would do at this point. One or two thing may sound a bit too obvious but maybe it benefits others too.

• Remove everything from your AD that is not absolutely necessary from basic operation. So that would be all cards on the IO bus, the esp-01 if you have that, etc. But leave the SD card reader connected. I would even disconnect the expansion card and power the main board straight on its barrel connector.
  
• Download a new (and latest) copy of UploadBinaryDue.zip and flash it to the DUE, as described on the install page as "The easy way".
• Format a SD card with FAT32. Download new card content from here and copy it to the SD card (all files!).
• Insert the SD card and power up the AD, with all switches down.
• Connect your terminal  to the DUE programming port, as described in the build instructions.
• AUX1 down will show the built-in programs.
• Switch 12 UP and AUX1 down should show the SD card content.
• If successful then you at least have a base configuration, and you can start adding components one by one until the SD card reader stops responding. Obviously you shut down the AD between every change.
• I would start first by re-flashing the DUE again, but now in "The more difficult way" with the Arduino IDE. Do not change any file.
  
• If that works, do that again but now with the changes made to config.h and host_due.h required.
• If the first startup doesn't work (no SD card) then the soldering of the main board would be my next suspect (missed solder joints, cold solder joints, solder bridges, etc).

Your proposed LED's (in the SD card slot?) will not help you. LED's are too slow (or rather: your eyes are) to see activity on the data lines, and 3v3 on the SD card reader can easily be checked with a multimeter. To properly see activity on the CS, MOSI and MISO lines you will need a scope. Even a cheap one like a DSO138 kit would work.

Good luck!

Op vrijdag 23 mei 2025 om 19:28:29 UTC+2 schreef r4r...@gmail.com:

[Walt Perko]

Hi,  

There is nothing but the Altair-Duino Pro computer, the µSD card, and finally, the USB cable to my PC running TeraTerm.   

IF you read earlier messages, I've tried more than three .bin files to various µSD cards.  

The original µSD card that was working in the past has not been written to and is not seen by the Altair-Duino Pro anymore.  

Testing with Address Switch 12 UP and AUX1 down only gives me the listing of internal default disks:  

00000000) [print this directory]
00000001) Calculator
00000010) Kill-the-Bit
00000011) Pong (LEDs)
00000100) Pong (Terminal)
00000101) 4k Basic
00000110) 16k ROM Basic
00000111) MITS Programming System II
00001000) Disk boot ROM
00001001) ALTAIR Turnkey Monitor
00001010) Music ('Daisy')
00001011) CPU Diagnostic
00001100) CPU Exerciser
00001101) Music system
00001110) Hard disk boot ROM
00001111) Multi-boot loader ROM
00010000) Dazzler Kaleidoscope
00010001) Cuter for VDM-1
01xxxxxx) [Read Intel HEX data from primary host interface]
10nnnnnn) [load memory page, nnnnnn=file number]
11nnnnnn) [save memory page, nnnnnn=file number]

The only other things I add to this Altair-Duino Pro is a serial cable to my SpeechBox, and the Native Port cable to the VDM-1 Terminal.  

If you look closely, I suggested a connector that plugs into the µSD card slot with a 3.3V Power LED, and "LATCHED" LEDs on the CS line, the DATA IN line to see if the Altair-Duino Pro is actually trying to talk to the µSD card.  

.

[Marco]

Okay, I give up, only trying to help here by suggesting to take a methodical troubleshooting approach.

AUX2 down with SW12 up should give the SD card content, not AUX1.

Op vrijdag 23 mei 2025 om 22:40:23 UTC+2 schreef r4r...@gmail.com:

[Walt Perko]

Hi, 

I can't find that in the documentation, but giving S12 UP and AUX2 DOWN does give me a list of the disks assigned in the µSD card.

It works on my Altair-Duino Pro #2, but on the Altair-Duino Pro #1 it's a blank screen.  

.

[Patrick Linstruth]

I think what we need is a simple Altair-Duino diagnostic program that just tests the hardware without all the “Altair” stuff.

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/c8f08c6f-bc2f-490c-997c-97af95def665n%40googlegroups.com.

[Patrick Linstruth]

So here is an issue… from the code:

  // check if SD card available (send "chip select" signal to HLDA status light)

  // SdInfo.h in the SdFat library says: Set SCK rate to F_CPU/3 (SPI_DIV3_SPEED) for Due

  // (84MHZ/3 = 28MHz). If that fails try 4MHz and if that fails too then fall back to 250Khz.

  // If neither of those work then something is seriously wrong.

  if( SD.begin(22, SPI_DIV3_SPEED) || SD.begin(22, SD_SCK_MHZ(4)) || SD.begin(22, SD_SCK_HZ(250000)) )

If SD.begin fails, it fails silently.

From the ‘h’ command:

Altair 8800 Simulator (C) 2017-2020 David Hansel

https://www.hackster.io/david-hansel/arduino-altair-8800-simulator-3594a6

https://github.com/dhansel/Altair8800

Firmware compiled on: Jun 12 2022, 09:29:13

 

Host is Arduino Due

 

RAM Start        : 0x20070000

Data/Bss end     : 0x200841D4

Heap End         : 0x200841D4

Stack Pointer    : 0x20087E78

RAM End          : 0x20088000

Heap RAM Used    : 0

Program RAM Used : 82388

Stack RAM Used   : 392

Free RAM         : 15524

Data storage     : flash memory (16K)

 

Registered ports for INP: 00 01 08 09 0A 10 11 12 13 FF

Registered ports for OUT: 00 01 08 09 0A 10 11 12 13 C8

 

 

Press any key to continue...

#if USE_HOST_FILESYS>0

  SwitchSerial.print("SD card file system");

  HLDAGuard hlda;

  if( SD.card()->errorCode()==SD_CARD_ERROR_NONE )

    {

#if SD_FAT_VERSION < 20000

      uint32_t numSectors = SD.card()->cardSize();

#else

      uint32_t numSectors = SD.card()->sectorCount();

#endif

      SwitchSerial.print(" (");

      SwitchSerial.print(numSectors/(2*1024));

      SwitchSerial.print("M, SDFat v");

      SwitchSerial.print(SD_FAT_VERSION);

      SwitchSerial.println(")");

    }

  else

    { SwitchSerial.print(" (card error: 0x"); SwitchSerial.print(SD.card()->errorCode(), HEX); SwitchSerial.println(")"); }

#else

  SwitchSerial.print(storagefile ? "STORAGE.DAT file on SD card" : "flash memory");

  SwitchSerial.print(" ("); SwitchSerial.print(due_storagesize / 1024); SwitchSerial.print("K)");

#if NUM_DRIVES>0 || NUM_HDSK_UNITS>0

  if( SD.card()->errorCode()!=SD_CARD_ERROR_NONE )

    { SwitchSerial.print(" (SD card error: 0x"); SwitchSerial.print(SD.card()->errorCode(), HEX); SwitchSerial.print(")"); }

  SwitchSerial.println();

#endif

#endif

Based on your output, your SD card is 1) initializing fine or 2) your firmware does not have NUM_DRIVES set to a value >0.

If the device is initializing ok, that would lead me to think there may be a problem with your SD card in which case I would go Marco’s route and create a new one from scratch. We have to stop assuming that things are perfect and start assuming everything is broke. If everything was perfect, it would be working.

With the plethora of conditional compilation options, it would be very nice if they were displayed somewhere from the configuration menu.. like maybe the ‘h’ command.

The code that mounts drives from the SD card also seems to fail silently without any indication that it didn’t work.

If I can find some time this weekend, I will send you updated firmware that will hopefully provide more info regarding SD card problems.

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/737ad01c-6f31-4b72-a7f6-841a381e3e10n%40googlegroups.com.

[Walt Perko]

Hi, 

Totally bizarre ... after trying at least three other µSD cards I finally got one to work properly.  Now I'm thinking some of the µSD cards I bought from a 5-Star seller on eBay are faulty ... grey market components.  

Now I want to find a new trustable vendor for 128MB µSD cards.  

.

[udo....@freenet.de]

r4r...@gmail.com schrieb am Samstag, 24. Mai 2025 um 22:15:09 UTC+2:

Now I want to find a new trustable vendor for 128MB µSD cards.

This is where the saying comes from: buy cheap, buy twice. Funnily always true.

Go to a local electronic parts shop and buy MicroSD cards produced by SanDisk or Transcent.

These are very well working brands doing what they should, and your local dealer will buy them from the manufacturer and not from some obscure Ebay, Amazon, AliBaba ... source.

 

[Walt Perko]

Hi, 

What electronics parts shop?  The last was Radio Shack several years ago.  This town is focused on gambling and partying.  

.

[David Williams]

Well, you didn't have any problem reading and writing them on your PC, right? If so, then you can't really say the cards are bad. It's more likely just a compatibility problem where either the card doesn't properly support the SPI mode used in the altairduino software, or there's just some small incompatibility that the software doesn't handle.

[Walt Perko]

Hi, 

Kiesub wants $35 for one µSD card.  I am poor, but even if I was rich, it's a waste of money.  

.

On Saturday, May 24, 2025 at 7:44:18 PM UTC-7 John Galt wrote:

you can try https://kiesub.com/ they might have what you like they are located in sin city south of the strip.

[Walt Perko]

Hi, 

The odd thing is all but one card is readable in the other Altair-Duino Pro computer, and all of them I can read/write on my PC.  

.

[Patrick Linstruth]

Would something like this work? $6 each.

https://www.amazon.com/SanDisk-3-Pack-microSDHC-Memory-3x16GB/dp/B089DPCJS1

You can probably get same day delivery in Vegas.

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[udo....@freenet.de]

r4r...@gmail.com schrieb am Sonntag, 25. Mai 2025 um 02:21:48 UTC+2:

Hi, 

What electronics parts shop?  The last was Radio Shack several years ago.  This town is focused on gambling and partying.

Here in Germany all the electronic shops I used to buy from as kid have closed their shops too. Still

some of the companies exist, they still distribute trustable parts from know vendors I can order online.

Also in the US some of the well known distributors still exist and you can order online. I know

because some of them also distribute here in Germany with a local branch office.

[udo....@freenet.de]

r4r...@gmail.com schrieb am Sonntag, 25. Mai 2025 um 05:43:28 UTC+2:

Hi, 

Kiesub wants $35 for one µSD card.  I am poor, but even if I was rich, it's a waste of money. 

A waste of money is buying parts that won't meet the specifications and so won't work

reliable. You have to throw them away and get some other ones. After enough retries

you'll sometime get working ones then. These likely are a bit more expensive than

unknown brands one never has heard about, but they just work reliable and with

regards to Micro SD cards they continue to work for many years.

You will get even poorer if you continue to waste your money on parts, that can not

be used for a long time. 

[udo....@freenet.de]

r4r...@gmail.com schrieb am Sonntag, 25. Mai 2025 um 05:44:46 UTC+2:

Hi, 

The odd thing is all but one card is readable in the other Altair-Duino Pro computer, and all of them I can read/write on my PC.

This is not odd, this is to be expected. Most users of MicroSD card likely will use them with some Windows PC.

If the cards won't work there they could not be sold in enough quantities anymore.

If such a card works in a Windows PC but not in some other device is, because there is a whole bunch of

of specifications and modes, and not every card will meet all specifications and work in any mode.

One might be able to figure from the product data sheet what works or what not, but that needs quite some

time. So just get known brands that are known to work on all devices with a MicroSD drive, saves all

the time wasted with trying not properly working stuff. 

[Chris Davis]

Were you trying to buy 128MB SD cards?  I learned when I first started that there were two types of cards back when 128MB cards were being produced.  SD1.0/1.1 and SD2.0 (not to be confused with Class 1, Class 3, Class 10, etc.). When micro sd cards were fairly new there were two competing addressing methods, SD1.1 and SD2.0.  SD2.0 was the winner and what we still use today.  SD 1.0 / 1.1 uses byte addressing, while SD 2.0 uses block addressing. My kit can only read the SD2.0 addressing method.

So if you buy random low-capacity sd cards, there is a 50/50 chance they will work.  Unfortunately I have never seen anything printed on the card showing what addressing method it uses.  One thing I have noticed is that SD1.0/1.1 cards will have the label printed in "portrait" as on the right, while SD2.0 cards will have the label printed in "landscape" as on the left.

This is not a guaranteed way to tell them apart, but has been pretty consistent in my experience.  If you want to be sure, buy an SD card with at least 4GB of storage.

So the cards you bought were not faulty, just the wrong type of card.

[udo....@freenet.de]

I think such cards won't work with a Windows PC either, as far as I know it uses a block driver for the cards dealing with 512 byte sectors.

[Chris Davis]

They will work on Windows.  I have a lot of them.

[udo....@freenet.de]

famousd...@gmail.com schrieb am Montag, 26. Mai 2025 um 18:49:48 UTC+2:

They will work on Windows.  I have a lot of them.

On Windows 11 too, or some older version from the time where this cards come from? 

[David Williams]

I would expect SD card drivers in the major operating systems to all interrogate the card, and handle the 1.1 vs 2.0 addressing. 

[Chris Davis]

I used my surplus of SD1.1 cards in my short-lived Apple 1 project.  I populated the cards using a Windows 11 computer.

[udo....@freenet.de]

famousd...@gmail.com schrieb am Montag, 26. Mai 2025 um 19:45:32 UTC+2:

I used my surplus of SD1.1 cards in my short-lived Apple 1 project.  I populated the cards using a Windows 11 computer.

Interesting, thanks. If this is still is supported in PC platforms, the question still is for how long. Doesn't really

matter for me, because I don't have such cards. But I noticed that in the SD support library for Raspberry Pi Pico

systems, I'm using in various z80pack picosim projects, support for the byte addressed cards was removed a few

releases before the current latest one. Reasons probably are the low transfer rates with byte addressed cards

vs sector addressing, and probably also to reduce complexity of the code and improve maintainability.

[David Williams]

I would expect PCs to support them for the foreseeable future. Nobody wants to find that Grandma stored archived their family photos to a card, and now none of their computers can read it. One thing that occurs to me is that support may also depend on the silicon in USB card readers. So it's possible that you might want to keep some older USB SD card readers around if you are concerned.

I can understand why some of these embedded platforms have dropped support, as they aren't usually used for general purpose storage uses, and program space can be at a premium..