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Are there any restrictions to using $F000 through $FDFF?


nathanielbabiak 2020-12-03 03:55 (Edited)

What are the restrictions to using the 3.5 kB block of memory at $F000 through $FDFF?

(Asking because the manual doesn't specify.)

I'm trying to avoid making any more cross-platform development tools (I feel like using the power of the PC is major cheating and it makes it not fun for me). I want to do everything within LowRes NX (except for the BMP file converter I just uploaded).

I'm obviously OK with minor cheating (that makes it fun) by using all of these, but only in this order...


was8bit 2020-12-03 05:18 (Edited)

Clever use of memory :)

My best guess is that any unspecified memory is most likely left in reserve for any unforseen updates in the future, so prolly best not to plan on using them... would require rewrites if they get used for something in the future..

Timo can best answer, as there are a few things behind the scenes not spelled out in the manual (like file#0)

Timo 2020-12-03 07:22

POKE in this area is not possible, but PEEK is.
I’m not sure now, there might be a bug allowing you to LOAD data into it, but I would fix this.
There should not be any chip connected to these addresses.

Timo 2020-12-03 07:24

File #0 is described in the manual in the chapter “Standard ROM Entries”

was8bit 2020-12-03 10:04

Ah, i missed that in the manual for rom#0.... thanks for pointing that out :)

nathanielbabiak 2020-12-03 12:22

Asked and answered then - thanks!

I assume this also applies to the other 512 bytes from $FE00 to $FFFF, correct?

Timo 2020-12-03 13:01

Well from $FE00 to $FFFF you have registers. You can use them, but things will happen ;)

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