Product specifications

The 512 has 64k of memory starting at 4000 hex and finishing at FFFF hex, with an
additional page of 16k switched out between 3000 hex and C000 hex. This additional
memory is switched in and out automatically and provided the code line does not pass
over its boundary the user is unaware of the paging system which is maintained in
hardware by a ULA.
It is possible to trick an MTX 512 into acting like a 500. To do this go into PANEL and
change the contents of memory location FA7A hex (61422 decimal), to zero, then
leave PANEL and type NEW.
This will leave the machine ready to load or have typed a new program as though it
were a 500.
There are a number of differences between the MTX assembler and other
assemblers.
Among these are the fact that there is no requirement to specify the origin of the
object code or provide a long list of assembler directives. As a result the assembler is
both easy to use and relatively fast, about 2 or 3 seconds for an 8k program.
The set of Z80 instructions concerned with loading the stack pointer with HL, IX and IY
are not directly available from the assembler.
They can be accessed in the following way.,
Normally Use instead
LD SP, HL DB £ F9
LD SP,IX DB £DD,£F9
LD SP,IY DB £FD,£F9
The VDP Chip.
Introduction.
2. 1.
The VDP chip has four video display modes. Normally only Text mode and Graphics
mode 2 are available directly from BASIC, but you can access the other two modes,
Graphics mode 1 and Multicolour mode, by creating your own VDP set-ups (See
sections 2.2 to 2.5).
Text mode provides a screen which is 24 times 40 character rows in two colours.
Multicolour mode provides a 64 times 48 colour dot display in 15 colours plus
transparent and 32 sprites.
Graphics 1 mode provides a 256 times 192 pixel display in 15 colours plus transparent
and 32 sprites.