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What is it

ReTuLa is a remake of the Acorn Tube ULA. The original is mainly (if not exclusively) used in almost all 'second processors' for the Acorn BBC.

ReTuLa is plug-in compatible with the original Tube ULA. It can simply be used instead of the original Tube ULA, or to replace a defective one.

Compatibility

ReTuLa is compatible with :

ReTuLa differs from the original Acorn Tube ULA in a few minor ways :

• DMA is not supported, i.e. ReTuLa is incompatible with second processors that use DMA. Only the Acorn 80186 Coprocessor does.
• FIFO 1 in parasite to host direction (the 'VDU FIFO') is 1 byte deep instead of 24. This seems a big difference, but, in general, it is completely unnoticable. Only in very specific, theoretical cases, VDU throughput may decrease by up to 4%.
• ReTuLa tolerates much higher access speeds than the original Tube ULA. This is largely academic, but may be useful in specific cases where the coprocessor is 'overclocked'.

More details

For more information, refer to the ReTuLa documentation, which you can read online or download.

Your own ReTuLa

ReTuLa is no longer available.