Another stupid flashing cable question HP-30b / HP-15C CE

[Maximilian Hohmann]

Hello,

I am desparately searching for my old flashing cable needed to convert HP-20/30b calculators into WP34/31s. I know that it is somewhere because I don't usually throw away things that are connected with calculators, unless they are completely corroded from battery leakage. Which is certainly not the case here.

But if I don't find it, would this be a way to make another one? Right now, flashing cables for HP-15C CE calculators are in plentiful supply at very decent cost. Could such a cable be modified using a USB-RS232 converter like these ones here from Aamazon? I hope the link lasts for a couple of days:
https://www.amazon.com/Isolation-Serial-...B09P4815BK
They can also be found on Aliexpress at 1/3 of the price, but Aliexpress links fill have a page of text...

This adapter can be jumpered to 3.3V , so apart from rewiring the cable with the pogo connector and the pusbuttons nothing else should be required. Or do I overlook something?

Regards
Max

[AnnoyedOne]

(09-18-2024 01:01 PM)Maximilian Hohmann Wrote:  But if I don't find it, would this be a way to make another one?

Personally I'd make a dual-use one.

https://www.hpmuseum.org/forum/thread-22...#pid191669

Sourcing the custom POGO connector is the only hard part IMO.

A1

[Didier Lachieze]

(09-18-2024 01:01 PM)Maximilian Hohmann Wrote:  But if I don't find it, would this be a way to make another one? Right now, flashing cables for HP-15C CE calculators are in plentiful supply at very decent cost. Could such a cable be modified using a USB-RS232 converter like these ones here from Aamazon?

This may be of interest for you : anyone need POGO cable for HP 20b/30b, HP 15C LE?, I have not built such adapter and cannot confirm if this works well.

[Maximilian Hohmann]

Hello!

(09-18-2024 01:09 PM)AnnoyedOne Wrote:  Personally I'd make a dual-use one.

Dual use has the disadvantage that if one gets it wrong, the calculator will be destroyed...
In any case a USB to RS232 converter will be required for the older calculators.

(09-18-2024 01:09 PM)AnnoyedOne Wrote:  Sourcing the custom POGO connector is the only hard part IMO.

It used to be difficult during the last decade, but now the HP-15C CE cables can be bought cheaply and they have the same pogo connector.

Regards
Max

[AnnoyedOne]

(09-18-2024 01:31 PM)Maximilian Hohmann Wrote:  ..but now the HP-15C CE cables can be bought cheaply...

I wouldn't say "cheaply" but not exorbitant either (unlike some). HP isn't the first to design a custom connector and never produce a cable for it. Fortunately someone did.

BTW I have a 15C CE cable. I don't require a LE etc one.

A1

[Dave Frederickson]

(09-18-2024 01:09 PM)AnnoyedOne Wrote:  Sourcing the custom POGO connector is the only hard part IMO.

Ten years ago I was selling parts to make a DIY POGO cable.
https://hpmuseum.org/forum/thread-183-po...ml#pid4013

Version 2.
https://www.hpmuseum.org/forum/thread-25...l#pid23831

[rprosperi]

(09-18-2024 01:01 PM)Maximilian Hohmann Wrote:  Hello,

I am desparately searching for my old flashing cable needed to convert

Max - Nothing to be desperate about, but I get it... I'm the same way. But no need to worry, the original will turn up shortly after you find or make a replacement.

Also, Eric Rechlin posted clear steps with photos about how to convert an "LE cable" to a "15c CE cable" so you can probably use it to do the opposite:
https://www.hpmuseum.org/forum/thread-19...#pid179488

[Maximilian Hohmann]

Hello!

(09-19-2024 10:10 AM)rprosperi Wrote:  Max - Nothing to be desperate about, but I get it... I'm the same way. But no need to worry, the original will turn up shortly after you find or make a replacement.

I started to work like an archaeologist now: From a backup disk I retrieved my email exchange with Gene Wright who sent me the cable. That was in 2013. So now I know how deep, or to which horizon (I think this is what geologists and archaeologists call the layers they investigate) I have to dig for the cable :-)

In the meantime I will order yet another HP-15C CE and programming cable just in case I have to activate plan B. Considering the value of one's time, buying a cable is a lot cheaper than tinkering together a pogo connector...

Regards
Max

[HPing]

Would Harald's USB and IR kit do the trick? Is it still available?

https://hpmuseum.org/forum/thread-8077.html

[AnnoyedOne]

(09-19-2024 10:10 AM)rprosperi Wrote:  Also, Eric Rechlin posted clear steps with photos about how to convert an "LE cable" to a "15c CE cable"...

I've looked at the photo's of the 15C LE/20B/30B programming cable and it doesn't look like a kit or DIY one. More manufactured and commercial (silkscreened details on the PCB).

I don't have any use for this cable. I already have a 15C CE one.

However out of curiosity:

Who made it?
Who sold it?
How much was it?

A1

[Uwe-001]

As far as i know: The old cable had a mechanically identical pogo connector, but the old cable was designed for a serial interface and the new 15CE cable for a USB interface. These interfaces have different voltages and the protocol layer, i.e. the “language”, is completely different. In my opinion, it is not worth tinkering with the cables. The cost of a cable is rather low. Did the manufacturer even provide firmware for the 15LE and 30B?

[Maximilian Hohmann]

Hello!

(09-19-2024 05:00 PM)AnnoyedOne Wrote:  I don't have any use for this cable. I already have a 15C CE one.

You never know... Have you ever looked at the WP34S and WP31S calculators? These were designed mostly by two individuals ("Walter" and "Paul", therefore "WP", both forum members at that time) but with much brainstorming (*) and contributions from other members of this forum. A sort of community effort which makes it very special.

(09-19-2024 05:00 PM)AnnoyedOne Wrote:  However out of curiosity:

Who made it?
Who sold it?
How much was it?

The original cables were supplied by HP. The one I have (somewhere - just did another half hour of digging and among other things found my transparent Ti overhead calculator about which we recently talked in another thread, but not the cable) was sold to me by forum member Gene Wright who was given a box of these cables by HP. As far as I remember he only charged the shipping cost for the cables he sent out.

Regards
Max

(*) Mostly endless discussions often ending in insults and people leaving the forum about whether to put the "+ - * /" keys to the left or to the right of the number keys ;-)

[AnnoyedOne]

(09-19-2024 05:55 PM)Maximilian Hohmann Wrote:  Have you ever looked at the WP34S and WP31S calculators?

Yes. Not interested. Neither are any other Atmel AT91SAML128 SoC based models.

(09-19-2024 05:55 PM)Maximilian Hohmann Wrote:  The original cables were supplied by HP

...given a box of these cables by HP.

Thanks. Interesting. So probably for HP in-house use only. I'm sure they have 15C CE ones too.

A1

PS: Good luck with your archaeological "dig"

[Eric Rechlin]

(09-19-2024 10:10 AM)rprosperi Wrote:  

(09-18-2024 01:01 PM)Maximilian Hohmann Wrote:  Hello,

I am desparately searching for my old flashing cable needed to convert

Max - Nothing to be desperate about, but I get it... I'm the same way. But no need to worry, the original will turn up shortly after you find or make a replacement.

Also, Eric Rechlin posted clear steps with photos about how to convert an "LE cable" to a "15c CE cable" so you can probably use it to do the opposite:
https://www.hpmuseum.org/forum/thread-19...#pid179488

Doing the opposite is a bit more involved since you need to add a level shifter somehow. There are basically two ways to do it. One is to convert the TTL-voltage out of the USB connector to RS-232 serial, and then use a RS-232 to USB adapter to plug that into your PC. The other, simpler way would be to convert the TTL serial directly to USB.

For the first, you'd need to get a level shifter like this:

https://www.adafruit.com/product/5988

Then get a USB extension cable, cut off the male end, and solder the wires to the above level shifter. You might need to solder one of the pins from the DE9 connector to VCC as well to provide power. Then plug the female end into the 15c CE cable, and the serial connector of the above level shifter into a USB-to-serial adapter, and then plug the USB-to-serial adapter into your computer. But if you don't already have a USB-to-serial adapter then that would be an added expense, so the second approach would be cheaper.

For the second, you'd want a USB to UART adapter like this:

https://www.amazon.com/dp/B07WX2DSVB

Then get a USB extension cable, cut off the male end, and solder the wires to the above adapter (just TX, RX, and ground), and plug your 15c cable into the female end of the cable. There are cheaper USB to UART adapters (like half the price) if you shop around but I prefer the FTDI-brand chip ones which tend to cost more.

I've never done this but in theory either of these approaches should work, and I know who someone did the second approach and it worked.

If you don't have a USB extension cable lying around to sacrifice, any cheap one would do, like this one:

https://www.amazon.com/dp/B002KKZAIU

[Maximilian Hohmann]

Thanks Eric

for this detailed reply!

(09-20-2024 04:34 PM)Eric Rechlin Wrote:  For the second, you'd want a USB to UART adapter like this:

https://www.amazon.com/dp/B07WX2DSVB

Then get a USB extension cable, cut off the male end,...

I ordered one exactly like that. And I don't even need to sacrifice a USB extension cable because I have some USB sockets, of which I thought I will never need them again, because everything is moving to type C now.

And just to confirm before I damage something: Is the pinout of the pogo connector the same between old and new programming cables, including the two buttons? I searched around the forum but did not find a lot about the new cables.

Regards
Max

[AnnoyedOne]

(09-23-2024 02:45 PM)Maximilian Hohmann Wrote:  ...Is the pinout of the pogo connector the same between old and new programming cables...

My guess is that RXD/TXD (serial) and D-/D+ (USB) might be different but the rest are likely the same. Can you meter them out to check?

A1

PS: Based on this

https://www.hpmuseum.org/forum/thread-19...#pid179488

D+ = TXD (green)
D- = RXD (white)

with the remainder unchanged.

PPS: As I recall with HP-15C LE/20B/30B an old version of SAM-BA is required. Also any existing firmware will be erased automatically. Thus unless you have the existing image you can't go back. With the HP-15C CE this isn't the case.

[HPing]

I have been researching the cable for some time. Complete instructions seem to have been lost to time.

Attached is a hand drawn pinout diagram with some instructions from Dewster of NJ (the complete drawing I think).

The links have some tips and some more info/links.

https://www.hpmuseum.org/forum/thread-16141.html

https://web.archive.org/web/201903022205...34s?Page=4



   

[Maximilian Hohmann]

Hello,

just some feedback - good and bad...

Yesterday I received the FTDI USB-serial adapter that Eric Rechlin suggested, the "DSD TECH SH-09C5", and connected it to an USB plug I had lying around (see pictures below).

It seems to work well with the "new" USB programming cable I received from the Calculator Store. I tried it under Windows XP and Windows 10 with MySamba.exe and with the wp34sflash.app on my MacBook Pro (MacOS 10.13.6 High Sierra). Exactly following the instruction in the WP34s manual, the procedure runs through every time, MySamba and the Mac app complete their data transfer in 18-20 seconds without an error message.

Unfortunately the caclculator only gets erased and not reflashed and ends up in a half dead/half alive state as seen in the third picture. Following advice in other threads I tried it with new CR2023 batteries and freshly charged recharcheable CR2032 (I avoid disposable batteries like the plague). No difference.

Any idea what does go wrong here? Could Samba be an alternative to MySamba with it's larger set of options?

On the positive side I can report that the same cable - without the USB to serial adapter of course - allowed me to install the latest version of the HP-15C CE within minutes (only on the Windows 10 computer unfortunately, which is not mine) including Geoff Quickfall's aviation package. Very nice!

Regards
Max

NB: I used transparent shrink wrap so that the cable connections can be seen:





The missing rows of pixels were caused by me because I disassembled and reassembled the calculator once too often when installing the crystal and IR diode modifications. Somehow I damaged the connection of the flex cable to the LCD glass in the process...

[AnnoyedOne]

(09-27-2024 01:09 PM)Maximilian Hohmann Wrote:  Unfortunately the caclculator only gets erased and not reflashed...

From what I know holding the ERASE button erases the current contents of flash (see my warning above) and invokes the (serial) bootloader on these older ARM SoC's. It would seem that is working but the download doesn't even though Samba thinks it does. I'd double check your connections (RXD/TXD reversed at one/both ends?).

The HP-15C CE firmware isn't protected (but could be) so the ERASE button just starts the bootloader. Reflashing and VoyagerSave work in XP/Win7 virtual machines (VM's) for me.

A1

[Eric Rechlin]

(09-27-2024 01:09 PM)Maximilian Hohmann Wrote:  Exactly following the instruction in the WP34s manual, the procedure runs through every time, MySamba and the Mac app complete their data transfer in 18-20 seconds without an error message.

Since it completed the transfer, that tells me the cable is working fine. I can see a couple potential problems. The most common is that with the 20b/30b (unlike the 15c CE), I believe you need to hit Reset after flashing in order to start the calculator. Though with several battery changes since, you've probably already essentially done that.

The next most common is that you may have installed a version of the firmware not compatible with your calculator as currently configured. Specifically I mean installing a crystal version of the firmware without the crystal working. To test this, try installing the non-crystal version (you didn't specify which version you installed, so I assume it's the crystal version). If that fixes it, then double-check your crystal/caps and how you soldered them, make any necessary corrections, and then try flashing the crystal version again.