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SD2iec Device now with TAP File Support


Ever wanted to load .tap image files straight into your C16/Plus4 with ease without the need of cumbersome cassettes, but frustated by lack of hardware support? Well it’s your lucky day.

princessc16a

princessc16b

Don’t be fooled by the C64 name. It is also compatible for the C16 & Plus4, as well as the Vic20. Unfortunately unlike the C64 and Vic20, at present the C16/Plus4 is unable to convert original cassettes to a Tap file image. However they have promised that they are working tirelessly on a solution for this which will hopefully be included via a downloadable firmware update eventually, of which can then be installed through your SD card. Scroll down to the Q&A for further news on this, and of course we’ll keep you updated on any progress.

As well as TAP files, the Princess also supports PRG, D64, P00, D71, D81 & M2I files. But for us we won’t need the latter four.

It is sensibly priced at €103.00 which is roughly around £80.00 UK for the Princess Pack which includes the universal kit necessary for the 264 series.

For more information, visit: www.manosoft.it

princessc16c

Finally, I have managed to make a few enquiries which they have kindly answered which you may find of use.

• Will there ever be a firmware upgrade to allow the dumping of C16/Plus4 tapes into a .tap file, and hopefully in the near future?

We’re working on it right now, of course, since it’s still in progress I cannot provide guarantees on the final result of the implementation, however the idea of implementing it is there.

• Why hasn’t it been possible to implement it?

Grabbing is a very critical process, SD2IEC is running at just 8Mhz and writing a continuos stream of data on an SDCard is a very very difficult task when using SPI (as SD2IEC has).

The real issue is not even the speed of data transfer (that anyway is not the one declared by SDCard vendors, that is obtained by clocking the SDCard @ 50Mhz, since we can clock the card no more than mere 4Mhz) but it’s the latency these cards have.

From time to time infact the internal processor decides that is time to do housekeeping and the card becomes unavailable to write data even for 400ms (this doesn’t happen while reading from SDCard).. you can imagine what could happen when you receive one pulse to be stored from tape every 100 us in the meanwhile…

C64 implementation was the first, three prototypes were implemented and went through a very long series of tests and simulations. The one provided is able to cope with a biturbo (the fastest loader) stream even on a Class 4 card provided it has good latency figures (SANDisk for example) this has been tested 5 times with a simulator streaming data for 50minutes each time.

Before releasing a C16 version, that requires more calculations since the clock base of the pulses is different, we want to make sure 1. that we don’t affect the quality of the initial C64 implementation, 2 that the implementation for C16 is as reliable as the C64 one. We don’t release things that are not perfectly working.

If I use a tape adapter to link the blue C64 tape interface located on the princess into the C16 tape port instead of going through the Princess’s standard C16 interface, would I then be able to create C16 .tap files?

Unfortunately not, the issue is not in the hardware. Hardware is ready to grab whatever signal is sent by the Datassette, the problem is in the firmware that must be modified to include this functionality.

C16 tapes (.TAP V1 style) have their pulses calculated on a different time base since C64 and Plus-4/C16 clocks are different, before storing pulse duration to the .TAP file then I have to make some calculations.

I cannot carry out the calculations in the usual way using multiplications and divisions or this would slow down so much the code that I will then not be able to efficiently buffer/save it to the SDCard.

I have already in mind what to do and I think it will work (even if I cannot be sure till it’s completely tested!). In the next days there are some other priorities to be fullfilled (manuals) but then I will start working on this.. If the quality of the implementation will be good for sure this feature will be added.

Do you have any other features for the C16 planned?

One idea was to implement also V2 .TAP specs especially for protected C16 games (actually there are not so many but there are some) but this would mean doubling the data rate of the pulses to be saved on the SDCard so it would make programming efficiency even more stringent and more difficult to achieve.

• Thank you for taking the time to answer our questions so concisely.

 


Categorized as: Hardware



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