
Damned if I can remember but I know there was something
which made me have to switch to MESS. I think the problem
worked itself out as it seems to play OK on DVE now.

Here's the public 64K Vectopia, but I've got to
dig around for the Vecmania copy.

The bank switching is terribly simple. The 6522
manual and a real Vectrex are not playing ball
in the same park though.

To sum it up, the high line is on pin 35 (PB6). When
you turn a Vectrex on, it's automatically high. Both
high & low banks hold the same loader code.

Here's the bank switch code:

Without notes in front of me, I don't even
remember what it's doing, but PB6 does not
actually toggle H/L the way the 6522 manual
says to do ! If you follow the manual to
set it high, it will send a single high
pulse then revert to low.

This took some experimenting to come up with this ...

LOWBNK  JSR     DPTOD0          ;SET THE LOW BANK !!!
        LDA     #223
        LDB     #$FF
        STD     $D002
        LDD     #$0100
        STD     $D000
        LDD     #$987F
        STA     $D00B
        STB     $D004
        JSR     RES0RF
        RTS

HIGHBNK JSR     DPTOD0          ;SET THE HIGH BANK !!!
        LDA     #$9F
        LDB     #$FF
        STD     $D002
        LDD     #$4100
        STD     $D000
        LDD     #$987F
        STA     $D00B
        STB     $D004
        JSR     RES0RF
        RTS
-- 

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