Portable Plus - Additional RAM

[J-F Garnier]

(03-20-2015 01:19 AM)Michael Fehlhammer Wrote:  But for the PP interface speed is really a matter: The transfer speed via PIL Box ( and this is also the IL-interface within the Arduino project ) is approx. 1 kB / sec.
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But nevertheless the SD-card project is great; especially when accessing a LIF disk using a HP 71b or 41C, speed is not a problem; the files are much smaller, and the calculators' IL interface is the bottleneck anyway.

The 1kB/s transfer speed with the ILPer/PIL-Box pair is actually limited by the USB link, which is no effcient for HP-IL byte-per-byte communication.
With the Arduino/SD-card-reader and the PP, the speed should be higher, maybe 2-3kB/s.

The PIL-Box/ILPer were designed for use with the HP-IL calculator family, the compatibility with the Portable Plus was not initially considered and was a nice surprise, since for years I though the Portable Plus required the SS/80 disk protocol until I found that the "Filbert" protocol (coming from the HP82161 cassette drive) was supported too and usable with volumes up to 16MB.

Anyway, even with the poor 1kB/s transfer speed, there is now a way to easily exchange files between the PP and a PC. I'm using DOSBox to access a 640KB MS-DOS volume shared with ILPer for this goal. It's not perfect because DOSBox has limitation, and doesn't always work as expected, but it is usable.

J-F