atari email archive

a collection of messages sent at Atari from 1983 to 1992.

new T-11 devsys rev.

(1 / 1)


			*** SYSTEM II STUFF ***

   There is a new DEVT11.LDA file available now. I have changed the downloader
to accomidate mmu offsets not equal to 10000 octal. This should come in handy
when you use more than 16 pages or when you set up your roms to use smaller
page increments.  The old ROMS should work fine as long as you only use 10k
increments.

	- Default page select offset is 10000 octal (page 0 select=00000,
	  page 1 select=10000.) However, if you want to use another
	  offset between two consecutive pages you can... The bottom 4 bits
	  of the page select word (address bits 16 thru 19) show the offset
	  /1000. (ie: 1 = 1000, 2 = 2000,...). 
	
		ex:
	             Output address = 30004000  (hex)  (default offset)
		     Download address = 40000 octal
		     MMU page offset = 10000 octal 
		     Page 3 (30000 octal) is selected for mmu page 0
		     Page 4 (40000 octal) is selected for mmu page 1
			

		ex:
		     Output address = 50024000  (hex)  (non default offset)
		     Download address = 40000 octal
		     MMU page offset = 2000 octal
		     Page 20. (50000 octal) is selected for mmu page 0
		     Page 21. (52000 octal) is selected for mmu page 1



					enjoy.. 
						jfs
Message 1 of 1

Jul 10, 1985