Host Memory Map
	A10000 - A24:D16 region, 64KB mapped to TMS34010 host regs
	D400 - A16:D16 region, 16 bytes. Unclear function. Might be the MMI-210


TMS34010  Memory Map after boot

00000000 - 2MB DRAM
C0000000 - TMS registers
F0000000 - ROM
F4400000 - AM85C30 Enhanced Serial Communications Controller
       0 - "Command" port for Channel A
	  10 - Data port for channel A
	  20 - "Command" port for Channel B
	  30 - Data port for Channel B
	       Channel B = AT keyboard, presumably A = serial port
F4800000 - Bt484 RAMDAC
F5000000 - Bits 4-7 mapped to front panel lights on write, front panel switches on read
           Other bits have unclear function
		       Most significant 4 bits are compared against F in one part of the firmware
			   3 least insignificant bits are preserved when 
FF000000 - 512KB VRAM


Bt484
	PCLK1 = 65MHz
	PCLK0 = 19.4MHz? (PCKL1/4)
	1/2 SCLK is fed to the TMS34010 VCLK
	serial clock of VRAM seems like it's maybe fixed rather than using SCLK
		this is based on observations of the behavior when using the 4bpp mode with
		appropriately adjusted params in the TMS34010 horizontal video timing regs
		you get a group of 8 pixels (4 of which are from VRAM and 4 are garbage)
		and then it seems to skip 4 pixels worth of VRAM and do another 8 pixel group
	only bottom 4-bits of each port is connected to VRAM
	bit 7 of each port appears to be always 1, other unconnected bits seem to be 0
	vga port doesn't seem to be connected to anythingg
	Weirdly, the firmware seems to fill the entire 256 entry palette RAM