Is there a ref doc/place for 34S how-to?


I have a 30b (and a large collection of HP RPN calcs...) and would like to convert to 34s - I've been reading the forum occsaionally, is there a how-to (re-flashing, overlay etc.) in one place that I can look at?



See message:

From Gene Wright:

1) Go here:

Download the file at the green button location.

2) Cable? You can get one from me but you will have to wait a week. I ask for $5 if overseas and $3 in the USA to cover the padded envelope I buy, postage and my gas to the post office. Email me at my forum email. :-)

3) Overlay? comes from Eric Rechlin.

4) How to do it? Download this PDF.

How to Flash a 20b


How to Flash a 20b

I was able to do it only after following the first requirement (Windows XP computer with hardware serial port). I had tried a patched SAMBA v6 both on Vista on Seven but it did not work, probably because of the USB-to-RS232 I used.


Get a cable with FTDI chip!


Thanks to all!


Which USB-serial converter did you use that did not work?


Feasso FCA-6, made in China:


FYI, another one not working for this purpose is Belkin's converter. Made in China, too, like almost everything else ...



The problem is that no manufacturer tells you the chip set on which their products are based. You will want one with an FTDI converter chip.


Note that SAM-BA 2.10 (the current version on the Atmel site) only provides support for serial port on Windows XP, on Vista and Seven it only provides USB support (and even though the USB to serial converter is plugged into a USB port, it still simulates a serial port).

Unfortunately currently there is only a serial cable available - does anyone know of a USB equivalent?

I don't know how well older versions of SAM-BA will work on Vista and Seven, as they will have to run in compatability mode or be modified, which creates its own problems - anyone have success on Vista or Seven with a USB-serial converter that can share their exact setup? Thanks


I used a USB to serial converter. It's a small printed circuit board, but is not a commercial product. It uses an FTDI chip.

It worked fine under Windows 7, but with SAM-BA 2.6. The newer SAM-BA 2.10 doesn't work with this configuration.


I have Windows 7 Pro 64-bit, since my old XP box died shortly before I decided to take on the WP 34s project.

Microsoft offers a legacy support if you have Win7 Pro or better in the form of the Windows Virtual PC and Windows XP Mode. I was able to get SAM-BA 2.10 to work with the built in serial port in my machine by installing it in the virtual machine. Took a little tweeking, but it wasn't too hard.

If you have Win7 Home, you would need a copy of XP to install, but it may be possible.


Virtual PC is still free but you need something to install within it. Any XP copy will do.


Hey Marcus:

With Windows Compatibility Mode, a free image of WinXP Pro is included with Win7 Professional, Enterprise and Ultimate; it just needs to be downloaded. That image is run virtualized under Windows Virtual PC. I installed it on my Win7 PC and it works great, though I've never used it. I still have several XP PCs still in service that run fine.



Hi Marcus,

Do you know a brand of USB to RS-232 converter that is known to have the FTDI chip?

Reading the response from Andrés to my other post, I wish to test the setup with my Vista machine, and add it to the "how to" article.

Edit: I see that FTDI (home page) sells modules and cables directly on-line, I'll look into it.


Edited: 8 July 2011, 9:47 a.m.


Edit: I see that FTDI (home page) sells modules and cables directly on-line, I'll look into it.

That would have been my suggestion.

Another way to figure it out: Try to download the appropriate drivers and/or manuals for the device in question before you buy it. You can normally tell from the driver names if it's an FTDI device.


Win7 and Vista have native drivers for FTDI USB-serial devices. We use the same chip in our custom television remote control programming interfaces, and I've never had to load a driver.

Edited: 8 July 2011, 5:11 p.m.


Do you know a brand of USB to RS-232 converter that is known to have the FTDI chip?

Name brand cables are not trustworthy. Too often they change their oem supplier without public notice and no longer have the expected components.

Simplified Arduino boards often use FTDI chips/cables. I'm not familiar with European suppliers (I've stumbled across many in the past but don't keep the links).

U.S. examples:

3.3v I/O cable

5v I/O cable

3.3v or 5v board

3.3v or 5v breakout board

SparkFun does quote Euro and Pound prices, so I imagine they'll ship. No idea if it is a good deal or not. They are pretty good in the U.S.


Edited: 10 July 2011, 1:11 a.m.


For these cables to work, you need to modify your 20b or 30b.

The first (3.3V) can be directly connected to the serial I/O pins of the calculator if you find the plug. None of the cables can be used with HP's cable. Someone should produce modified cables where the voltage converter is replaced by the 3.3V FTDI cable. For initial programming of an unmodified 20b or 30b you'll need the "Erase" button.



I was able to search for "FTDI USB" and came up with several links.

This is the cheapest adapter I found on Amazon that specifically lists the FTDI chipset:

"Mini Adapter has one Status LED and uses FTDI Chip for up to 230K Speed."FTDI adapter


This is the cheapest adapter I found on Amazon that specifically lists the FTDI chipset:

"Mini Adapter has one Status LED and uses FTDI Chip for up to 230K Speed."FTDI adapter

Notice anything different about that compared to the ones I listed?

Unfortunately that one and many others I've seen on Amazon all are specified to do a conversion to RS-232 voltage levels (-5v to -12v and +5v to +12v) which may or may not work and may or may not fry the 3.3v (0v and 3v) signaling used by the calculators. It seems like it would be cheaper to not do the conversion but quantities of scale...

Adding "header" to the search does turn up: USB to 3.3v TTL Header like FTDI TTL-232R-3V3 with a description that claims "Utilizes newest FTDI FT232QR chip"

With that said, sometimes the cheap ones don't actually do a conversion to RS-232 voltages... (Which violates the RS-232 specification, but much RS-232 hardware does work and recognize the signals never the less.) I just cannot recommend anything like that, because you are relying on not only unspecified feature, but a feature contrary to the specification.


We are guessing there's a correlation between "FTDI" and "USB 2.0". Holds for a few samples I googled. I leave this to the experts to confirm or deny, however.



Sylvandb, you're mixing things up a little.

HP furnishes a cable with the special plug to match the connector of their latest calculators. This cable has a plastic housing with two buttons ("Reset" and "Erase") in the middle and a standard 9 pin header on the computer end. This plugs into a standard RS232 port or a serial/USB converter. Using the latter works only with an FTDI equipped converter, who knows why.

FTDI makes cables which operate directly on the lower (and inverted) levels available on the calculator socket but you cannot use these with the cable made by HP. You have to make your own connection directly to the board, e. g. with a stereo jack like I did. The 3.3V cable is the one use in this case.


Following Marcus' advise I got
this one and I can confirm it works perfectly on all our computers Win XP, Win 7 etc.


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