sam coupe demo mnemodemo][ mnemotech zx spectrum 48k 128k +2(a/b) +3

zx spectrum 128k mb-02+ dma hc200 didaktik scorpion atm pentagon
putting themnmnmnmnemonic in mnmnmncoding
SCREEN MODES- INTRODUCTION -There are four screen modes used in the Coupe, each using varying
amounts of memory and each having different attributes for use by the programmer.The hardware pointers which display the contents of the memory are controlled by the VMPR, Video Memory Page Register (252 dec).
By using the lower 5 bits of this register we can access up to 32pages of video screen memory. It must be noted that modes 3 and 4use 24 kilo-bytes, which go over the page boundary of 16kilobybtes. Where this happens, the video addressing hardware wraps into the next page within the same block. For example:
By entering page 12 to the VMPR, video wraps to page 13The same applies to any page and the principal of even to odd always applies.
- MODE 1 -32 cells x 24 lines in 2 colours from 16 out of a palette of 128colours, giving 768 character cells (8 x 8) using 6 kilobytes of bit mapped memory and 0.75 kilo-bytes of attribute memory. This mode emulates Spectrum memory mapping.
- MODE 2 -32 cells x 192 lines in 2 colours from 16 out of a palette of 128colours, giving 6144 character cells (8 x 1) using 6 kilobytes of bit mapped memory and 6 kilobytes of attribute memory. This mode has contiguous memory addressing in two blocks.
- MODE 3 -512 pixels x 192 lines in 4 colours out of a palette of 128 colours,giving 98304 dots using 24 kilo-bytes of memory. This mode, when used with a character set 6 pixels wide, will give 85 characters per line.
- MODE 4 -256 pixels x 192 lines in 16 colours out of a palette of 128 colours,giving 49252 dots using 24 kilo-bytes of memory. This mode is ideal for graphic display, and when used in conjunction with LINE INTerrupt
register can display the full 128 colours on screen.
Mode 1 32 x 24 character cells per screen, each cell capable of 2 colours; 16 colours selectable from
12e; Spectrum-attribute compatible. - and almost as slow with video ram contention runs 10-20% faster than speccy
Mode 2 As mode 1, but with 32 x 192 cells, each cell capable of 2 colours: 16 colours selectable from
128. similar to the timex and multitech mb-02+ only multitech uses dma timex and sam use an extra 6kb of ram instead of768 attribute bytes like the speccy has.
Mode 3 80 column text display - 512 x 192 pixel screen; each pixel selectable for colour; 4 colours per
line selectable from 128 - supposed to be 16 colours using hmpr bits 5&6 but so far...
Mode 4 256 x 192 pixel graphics screen; each pixel selectable for colour; 16 colours selectable per
line from 128.
- SCREEN MEMORY LOCATION -A complete screen takes 6.75K in mode 1 and 12K in mode 2 (not including a 2K gap between pixel and attribute data). In these modes the memory containing the screen can be switched in at any 16K boundary. The paging system means that the other 16K RAM page in the same half of memory will page at the same time as the page containing the screen. Modes 3 and 4require 24K and thus two 16K pages. You can either leave the screen memory permanently paged in or just page it in when you want to read it or write to it, providing your screen handling code is paged in at the same time!The ROM switches in the screen as it requires, in sections C & D of the memory map (8000H).

Category:

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[rogerjowett]

actually faster to transfer the emulator and the demo disk an install than to sit and wait for the ridiculously badly designed youtube website to stream dreadfully poor quality video over the internet

couldn't someone just stuff an active x control java applet into the utterly whoops adaisy we cant even detect hardware mpeg playback macrodynamic sorry adobe dreadful take me to your website to transfer the flash pleader

[SerbianCommie]

i havent known that SAM Coupe has such advanced graphics features

[rogerjowett]

@SerbianCommie didn't

u didn't know

well its kind of liek teh timex only four colours in hi rez and 16 in speccy which makes 24kb screen so its almost as slow as the 16mhz 65c2 coprocessor for teh bbc master! mind you mode 2 was 12kb timex hi colour liek the MB-02+ DMA induced multitech mode only timex and sam do it with ram rather than using the dma to catch the scan line and alter attributes - what a shame they didnt bother with a 32byte attribute buffer in the ula+

[AlexAcE1]

what's this?

what do u want to show here?

curious

[Plex001]

I like the sounds! :)

[kalateur]

Last part of video is really amazing!! almost like a Amiga!!