By chance I bought a Sharp PC-1248 in April 2024 and when it arrived, I realised that it was originally sold as a navigation computer. A quick test showed that the navigation software was missing, so I searched the Internet and found that the program was written by Mike Pepperday. I wrote a short e-mail to Mike and learnt that he had a website, but due to various complications only a copy at archive.org survived. Unfortunately archive.org did not mirror the attached files, but Mike was so kind to attach them in his answer to me.
As a collector of Sharp Pocket Computers, I'm very interested not only to maintain these computers and keep them in working condition, but also in preserving the software they used to run. I initially reproduced with Mike's approval the content from his archived website here but in the meantime Mike has his website up and running again, so I only kept the part with the actual software that is needed to make a Merlin II out of a PC-1248.
Using information from Mike Pepperday's website as well as a couple of programmed PC-1248 that Mike sent me, I was able to retrieve the source code of the needed programs that make a Merlin II out of an ordinary PC-1248. The programs are named P4 and MM (or G4 and MG for their German versions) and details about what and how they do it can be found on the pages Merlin II main program and Merlin II PC-1248 tech info.
The programming process is straight forward: the program P4/G4 is loaded from tape and run. Its purpose
is to store constants in RAM that will be used by the main program. Then it runs checksum routines that
must be passed before it wipes itself and loads the main program MM/MG. The whole process takes some
minutes to complete and in the end entering 4 DEF L will test Merlin II. An error free
Merlin II will return 999.
The software below is available in digital formats that must be converted before they can be loaded by
the
PC-1248. Anyone who wants to do that will have to use the Pocket Tools (external link)
to
create the audio signal needed to run CLOAD. Please read the instructions included in the
Pocket Tools archive for more information about how this is done.
If you have a Merlin II that needs reprogramming and you can't do it yourself, get in touch with me via contact and I'll either help you through the process or program your Merlin II for free, if you cover the cost of shipping.
Important Information when studying the source code: The Sharp Pocket PC-1248 uses a special character for the so called exponential or scientific notation 𝔼, which the Pocket Tools replace with the Euro sign €. When € occurs in the source files below (.BAS), it is treated as 𝔼 when uploading a program. Pi must be written Π (uppercase π) to be recognised as such.
All the files below are also available in one archive: MerlinSoftware.zip(28 KiB).
For more information see also Merlin II PC-1248 tech info. Click on the links below to download the files you need:
For more information see also Merlin II main program. The source files below follow the needed conventions and can be processed directly with the Pocket Tools. Again, click on the links below to download the files you need: