DESCRIPTION OF BUSY's on TIM-0 & 1 & 2
	======================================


		*** DRAFT -2- ***	MP-UCL, 05 Feb. 2002



1) On PLD-2, there are internal busys, which get asserted while any of the
   internally-generated TTC(x) functions are being generated. Used to be
   called /BUSYA, /BUSYB, etc.... Now I think they are called "BUSYECR",
   "BUSYFER", etc.

   They should be as long as the SCT serial code for each 'fast command' :

	L1A :			3 clocks
	BCR, FER, ECR, spare :	7 clocks
	CAL :			27 + pipeline-delay-to-trigger + 3 clocks


2) "OA_BUSY" is an OR of all above BUSYs and of "TESTBUSYON"

   - ( "OA_BUSY" in the Status Register 6 bit 2 should NOT get
     asserted when "TIM-OK" goes LOW = ie. not OK )


3) "TESTBUSYON" is a busy line which is enabled by Commands Register 1
   bit 13 "EnTestBusy", and cleared by Commands Register 1 bit 14
   "ClrTestBusy" and/or by "OA_RESET"

   "TESTBUSYON" is set by the next L1A after being enabled, and should
   prevent any internally-generated or externally-received fast commands 
   after this L1A being acted upon

   "TESTBUSYON" is also output to the Status Register 6 bit 14


4) "INTBUSY" is the "OA_BUSY" shown in the Status Register 6 bit 2

   - ( "INTBUSY" & "OA_BUSY" in the Status Register 6 bit 2 should NOT get
      asserted when "TIM-OK" goes LOW = ie. not OK )


5) "VBUSY" is set in Commands Register 1 bit 7


6) "EXTBUSY" is the OR of externally-input "NIMEXTBUSY" and 
   "ECLEXTBUSY" from the front panel

   It is also a bit 0 in Status Register 6


7) Front panel signal "NIMEXTBUSYIN" is enabled onto the "NIMEXTBUSY" line
   by selecting link LK2 pins 1+2


8) Front panel signal "NIMEXTBUSYIN" is enabled onto the "EXTRODBUSYIN"
   line by selecting link LK2 pins 2+3

   In case of par. 8) the "EXTRODBUSYIN" should be grounded by selecting
   link LK2 pins 3+4


9) "BUSYOUT" is the OR of  a) "OA_BUSY" ( same as "INTBUSY" ) enabled
				by "EnIntBUSY" in Enables Register 0 bit 7

			    b) "EXTBUSY" enabled by "EnExtBUSY" in
			       Enables Register 0 bit 15

			    c) "VBUSY" from Commands Register 1 bit 7

			    d) "RODBUSY", enabled by "EnRODBUSY" in
			       TTC Enable Register 12 bit 7

    It is also a bit 3 in Status Register 6


10) "BUSYOUTB" is the buffered "BUSYOUT" sent to 'TIM BUSY' LED


11) "nBusyTrig2" is same as "BUSYOUT" above, but with the "OA_BUSY" ( same
    as "INTBUSY" ) being permanently enabled ( there is no "EnIntBUSY" )


12) "NIMBUSYOUT" is a front panel output of the "BUSYOUTB" signal
    ( buffered version of "BUSYOUT" ), and can be selected by link LK4
    to be either +ve or -ve going


13) "ECLBUSYOUT" is a front panel output, which is selected by link PL20
    to be either "BUSYOUTB" signal as above ( PL20 pins 1+2 ), or the
    "MEXTBUSYOUT" signal ( PL20 pins 2+3 )


14) "MEXTBUSYOUT" is the "EXTBUSY" signal enabled by "EnExtBUSY" in
    Enables Register 0 bit 15

    It is also a bit 1 in Status Register 6


15) "VRODBUSY" is set in Commands Register 1 bit 8


16) "RODBUSYOUT" is a front panel output, which is selected by link LK1 to
    be either NIM-type signal "TIM_BUSY" ( LK1 pins 2+3 ) - which can be
    selected either +ve or -ve going by link LK7 - or TTL-type signal
    "FP_BUSY_OUT" ( LK1 pins 1+2 )

    - ( "ROD_CRATE_BUSYOUT" ( ie. also "FP_BUSY_OUT", 
      "FP_ROD_CRATE_BUSYOUT", "ROD_CRATE_BUSYOUT, "TIM_BUSY_OUT",
      "TIM-BUSY" and "RODBUSYout" ) should NOT get asserted when "TIM-OK"
      goes LOW = ie. not OK )

    -  ( it should BE asserted while the TIM is in "SAMODE" )


17) "FP_BUSY_OUT" is the "FP_ROD_CRATE_BUSYOUT", which is the same as
    "ROD_CRATE_BUSYOUT


18) "ROD_CRATE_BUSYOUT" is the OR of

		a) masked OR of all the ROD-BUSY(x) signals received from
		   TIM backplane ( see ROD Busy Register 16 and ROD Mask
		   Register 15 )

		b) "EXTRODBUSYIN" input from the front panel ( see par.8 )
		   and enabled by the "EnRODBUSY" bit 7 the TTC Enables
		   Register 12

		c) "VRODBUSY from Commands Register 1 bit 8

                d) "SaMode"  from Status register 6 bit 11


19) "RODBUSYout" is the "ROD_CRATE_BUSYOUT" set in bit 7 of Status
    Register 6

20) "TIM_BUSY_OUT" is the "ROD_CRATE_BUSYOUT" sent to TIM backplane
    J3 pin 21D


21) "TIM-BUSY" is the "ROD_CRATE_BUSYOUT" sent to the 'ROD BUSY' LED


22) BurstBUSY, SeqBUSY, SinkBUSY - see Status Register 6




				       This version :  MP-UCL, 05 Feb. 2002


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