Re: cassette port dongle
Date: 2006-09-03 22:49:43

> I am not sure which registers...  Looking at Marko's I/O map, I see bits 
> 3, 4, and 5 of $01 and bit 4 of $DC0D, I will start looking for reads 
> to these addresses.

$01 is correct. Turbo Assembler and Turbo Assembler macro+ used such a dongle, I 
think it was a primitive 506-Timer chip to short circuit some bits from $01. I 
could never check because the dongle was sealed with molten black plastic. :(

The protection check involved many times commands like

bit $01
bvc protection_bad 


lda #$and_mask
and $01 
bne protection_bad  (or was it BEQ prot_good, etc.)

and variations thereof.
(lda $01, lsr a, bcc protection_bad, etc.)

Checksums over the whole ram memory area of Turbo Asm were also in common.


Ein Service von

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