PAL-1 what software makes use of the 2nd RIOT

[Stefan S]

Hello friends,

as here is likely the best place to ask, as most PAL-1 users are likely in this group, which software does not work without the 2nd RIOT expansion?

Thanks

Stefan

[Hans Otten]

There is quite some software and documentation that expects a second RRIOT to be present.
Some First Book of KIM-1 program use the time of the second 6530. Easy to change.
Examples in documentation over the years with I/O all expect the application connector having the I/O lines of the second RRIOT available.
Books like Microcomputer experimentation, The M. de Jong book etc all rely on I/O lines.

MICRO ADE (assembler/editor) is an example of an application that controls the motor of cassette drives for file storage. 

The same applies for more recent additions like the Corsham SD Card shield, the SD card extension, the 1541 emulation.

It is not a KIM-1 if a second RRIOT is not at least an option! 

[Stefan S]

As already mentioned the IO would be there in opposite to KIM-1 even with a working PB6.

More interesting for me are the cases that use the timer of the 2nd 6530.

If it's up to 5 I would say manual patching is the way to have a VIA Timer compatible version.

If its between 5 and 9 it's worth to create some scripts for auto patching.

If it's 10+ I would look into building some 74 TLL replacement, my estimation is that it needs between 5 and 10 ICs.

My idea was to optimize the tape interface (Hypertape) and make it like the one on the C64 and other with motor control and switch sense.

I have some other plans for much cheaper mass storage solutions so I don't care for the Corsham SD-Card extensions.

The VIA counter has a range of 0-65535 while the RIOT hast a pre-divider of 1, 8, 64 and 1024 and can count from 0-255 what means effective 0-255, 0-2040, 0-16320 and 0-261120

That means as long as the pre-divider of 1024 is not used the VIA can emulate the RIOT counter easily. If it is used you still can let the 6502 count to 4.