Using CMOS on the MTXplus

[Martin A]

The MTXplus includes a Real time clock with a small amount of battery backed ram.

At the moment of the 114 or so free bytes in the RTC we're using 4.

Thanks to Tony's versatile CPU clock design the are 16 different CPU speeds available, that's one byte.

Another determines which of the 4 available partitions the SDX rom will boot from.

The final 2 set the default screen colour in basic and panel, but only in the hacked 80 column basic.

So, there's another 110 bytes - any idea's ???

The current boot screen

CMOS.jpg (28.18 KiB) Viewed 33865 times

More relaing colours in panel

panel+.jpg (27.62 KiB) Viewed 33865 times

[Martin A]

The latest rom build for the MTXplus

Not much new on the boot screen, the confirmation of the VDP output mode is about it.

The current boot screen

boot2.jpg (52.73 KiB) Viewed 33807 times

Inside the setup screen has lots of options.
There's 3 built in base setups, for the most common scenarios.

From there the screen colours in Basic, Panel and Mono CPM can be selected.
The Date and time can be set, as can the boot drive for the SDX, the VDP output mode.
For fine tuning, the amount of memory seen by basic (0-13 32k pages + the base 32k) and the CPU speed can be tweaked (there's 16 steps from 4mhz to 16mhz).
All the extra's mean that the CMOS usage has doubled, but there's still over 100 bytes free.

The setup screen

setup screen.jpg (55.39 KiB) Viewed 33807 times

[Dave]

Martin

awesome as ever! You've really done some sterling work with the MTXPlus+ ROM . . . .

folks won't know how impressive it is until they try it - I really need to make those PCBs available soon!


regards
Dave

[1024MAK]

If you'll after something that will eat up a bit more CMOS SRAM space, how about user selectable custom boot screen colours, option of a Z80 inside logo, and maybe owners name / nick name and phone number? In case of theft...

Anyway, keep up the good work

Mark

[Martin A]

The user's name - interesting idea. I wonder what BASIC would think of "USER USER" as a command to print the name....

The boot screen colours follow the ones for Basic, so they're semi definable.

Z80 inside logo wouldn't have been possible with the 40 column screen. As the character definitions and the screen map overlap and any logo has to be defined as characters as this is text mode. With ASCII taking up 96 characters and the cursor another, there were only 31 left to construct the current logo.

Now we're running in 80 columns, the characters from 128 and up are available for additional designs.

If you're wondering how we get more than 2 colours on the text screen, lets just say, you need to flash very slowly.