Calculator blog

Finally we received the cables (just 300 units of the 1000 ordered- the rest after Chinese new year), and we are shipping them to customers already. Hold on- yours is about to be sent if it hasn't yet.

On the other hand, we have created some pages with information on the use of the cable. We have just focused on the current use, but there will be more! So I would also consider obtaining a 3D printed back door - to avoid having to carry a screwdriver with you!

I am beginning to learn the HP16c through the HP16c mode in the latest HP15c CE. It is very expensive to get an original HP16c!

Unfortunately, the HP16c mode has a very nasty bug whereby the DEC screen mode does not represent well the X register's contents. The register contents are OK - it is the screen view that is wrong. It happens with some values only - but enough to be unuseful for real life use.

A member of the hpmuseum.org community developed a change in three positions of the original ROM. It is not that the original ROM was wrong - it was the emulator (which was designed for calculators that just use numbers in BCD) that could not manage some of the hexadecimal higher values. With reference to the original ROM memory space, the changes are the following:

06ef:000 (was:346)
06f0:000 (was:1cb)
0718:3ac (was:17a)
(addresses are the 10-bit word addresses expressed in the 16c ROM space - beware that you need to add the offset from the beggining of the firmware to the beginning of the HP16c ROM, and that the HP15c firmware is arranged in bytes, so that two bytes make a "nutbyte" of 10bits. You also need to consider that the memory is arranged "little endian".

We are now patching the HP15c CE calculators for the customers that ask for it. We are also offering the patching service for calculators in our customer's hands - in this case for a fee.

We will also receive soon a patching cable, valid for the HP15c CE, the latest HP12c (after 2015) and the HP10bII+ (anyone considering adding RPN to the HP10bII+ ?)

We have found finally a producer that has access to pogo pins at the same picth as the one in the HP calculators. It is a different pitch from the industry standard 2.54mm - which makes it difficult to find a replacement.

Now we are discussing the prices - prior to this, we did not even know with whom to discuss! Let's hope to strik an agreement and be able to have a product for Christmas.

Here are some pictures now drawn by the factory: