Additional clockports for the A1200 ?

[platon42]

Actually, the Quaddddroport is supported in the Subway driver -- but I never have tested it and AFAIK never got reports back from users.

And no, clockport cards cannot be chained -- there are only four address lines (!) and 8 datalines creating a mere address/register space of 16 bytes. The subway needs all of them to operate. Clockport cards are some kind of magic

The only exception to this chaining was the Melody soundcard, which can be chained with a Twister serial port (the cards would share the address space). But it will only work exactly this way and no other.

Ah yes, the following Zorro card clockports are supported by the Subway:

/* Highway */
/* Unity Prototype CP 0 */
/* Unity Prototype CP 1 */
/* X-Surf CP 0 */
/* X-Surf CP 1 */
/* ISDN-Surfer */
/* VarIO */
/* Buddha flash */
/* Kickflash */ (the last one only the next release of the driver)

[platon42]

@Steady:
While this is valid for the original A1200 clockport, zorro clockports have the same address offsets, but with a different base and often use faster timings. This no problem for most clockport devices. And nearly all of them at least support one of the zorro clockport cards -- hacking them into using a different one with different base is very simple then. The Quaddddroport uses the same addresses as in the original A1200, but has three additional clockports at 0x4000 offsets.

[platon42]

> The design I posted had a problem with the Interrupt handling, all the IRQ lines were tied together! So with 4 devices, if 1 signals an interrupt, it would fight the other 3 IRQ lines!

Is this really a problem? I thought the IRQ line (INT6) was tristate anyway.