	.sbttl	System Definitions

	; These absolute addresses are used to access the various
	; i/o devices in the system.

					; BYTE read/write
	sys$clk		==	0x7F00	; system clock
					; <7>	- clock ready
					; <6>	- clock interrupt enable
	sys$wait	==	0x7F00	; acquisition inhibit
					; <5>	- !(external inhibit)
	sys$id		==	0x7F00	; system code number
					; <3:0>	- communication channel

					; BYTE read/write
	clr$clk		==	0x7F01	; clear clock interrupt / ready

					; WORD read/write
	acq$dac		==	0x7F02	; LED driver pulse amplitude DAC
					; <11:0>

					; BYTE read/write
	acq$slct	==	0x7F04	; acquisition select
					; <7:0>	- selection code / mode
					; <7>	- enable LED pulsing
					; <5> = 0	- enable channel
					;	<4:0>	- select 1 of the 32
					;		  input channnels
					;		  and corresponding
					;		  pulsing channels
					; <5> = 1	- enable temperature
					;	<4>	- enable pulsing
					;	<3:0>	- don't care

					; WORD read only
	acq$wait	==	0x7F06	; acquisition inhibit
					; <15>	- external inhibit
					; WORD read only
	acq$adc		==	0x7F06	; pulse height acquisition ADC
					; <9:0>

					; BYTE read/write
	sys$ser0	==	0x7F08	; 6850 serial port #0

					; BYTE read/write
	sys$ser1	==	0x7F0A	; 6850 serial port #1

					; BYTE read/write
	sys$ser2	==	0x7F0C	; 6850 serial port #2


					; BYTE read/write
	sys$led		==	0x7F20	; LED control and status registers
					; 32 LED control and status registers
					; begin at this address
					; <1>	-	green LED control
					; <0>	-	red   LED control

