Timer Signal Relationships - Texas Instruments 990 Manual

N
I
N
°'
LOGIC
SHEET4
LOGIC
SHEETS
BASIC CLOCt; INTERVALS
DOT INTERVALS
CL~ ,NCLK
DOT RO
DOTRI
DOTR2
DOTR3
DOTR4 ,NDOT4
DOTRS ,NDOTS
DOTR6, NDOT6
D2TRUSQ
D2.TRU6Q
LINE COUNTEf! TIMING
TV SCAN .INES:
K99L NCIOT6Q
L!NEAQ
LINEBQ
LINECQ
LINEDQ
LCOL
NENDL NDOT6Q
~KLC
~KLL
1 0 1 2 1 2 1 3 1 4 1 5 1 6 1 0 1 1
I I I I I I I I I
_fU1Jl__JLfl_JU1__IlJ
_fl
-+j91N~_t_____r--i_
_ _ J I
-~·
_ _ f l _ _ _ ___ _J
_ _ _ ___fl__ ____ ·--··
_ _ ____.L__, __ _
_ _ _ _ _ _ J L _ _ _ _
-,_ _ f l _ __
_ __r-----,__ __ ,
--i___r------,_ ___ ,
j..-----··
636 nsEC
------l
11.004 MHZ
1.57 MHZ
0 ' 2 3 • 5 ~ 7
s
9 10 11 12 13 14 15 0
-~--­
_ _ _ __s---,_
_c--
635µ5EC
--=i_
TllllllllJT-
~
TYPIC1\L ROW FOR 1920-CHARACTER
DISPLAY
_L_Lli_LLL I I I I I I I I _LL
L__fULnJlJl.SL.n__n_
-L_.JL._fl___Jl_J--i_
-,_ ___
__r--i__~--i_
L._
_J L_
_r----·--
1018 •SEC
---::i._
1111111111 lllllTT
TYPICAL ROW FOil 960--CHARACTER DISPLAY
6 7 S 0 I
15,720 HZ (63.5 SEC PERIOD)
INCREMENT LINE
COUNTE~!
LINE COUNTER (LSB)
LINE COUNTER (MSB)
- - - - - - LAST LINE OF ROW
____ _L__
END FRAME
ITITI
LOAD CHARACTER COUl~TEI~ LAT•:H
~RESET
CHARACTER COUNTER LA'TCH
RESET OF LINE
TIMER LOGIC VOCABUL.ARY
COUN'TER AT MASTER
LOGIC SHEET
5 ,4
(C)136321 A
MNEMONIC
CSQ
ENDI- ,NENDL
HBSI.
HDEtlDL ,NHDENDL
HDE<lSL
HDSL
HSBCI
HSQ
KADC-11
KCH<l-2
K99L ,NK99L
LCOL.
LINE (A,B,C,D)Q
NKLC
NKLL.
NRSCSL
VBL
VSB<;
VSQ
KLQ(0-7)
DESCRIPTION
COMPOSITE' SYNC FF
TWO HERTZ CLOCK
RESET OR END
OF FRAME
ENABLE RESET OF CHARACTER COU1'TER ANO LINE COUNTER TO ZERO ("OM DECODES A SPECIFIC ROW, LINE AND CHARACTER 99 TO
DETERMINE END.OF FRAME)
ENABLE HORIZONTAL BLANKING (OCCURS EVERY LINE)
ENABLE RESET OF COMPOSITE SYNC FF' (EACH LINE) EXCEPT DURING VERTICAL SYNC
ENABLE RESET OF COMPOSITE SYNC •F (EACH FRAME) DURING VERTICAL SYNC
ENABLE HORIZONTAL DRIVE/SYNC
HORIZONTAL BLANKING INTERVAL (El/ERV LINE)
HORIZONTAL SYNC INTERVAL (EVERY LINE)
CHARACTER ADDRESS COUNTER (DETERMINES A CHARACTER ADDRESS FOR EVERY INTERVAL WITHIN A FRAME) BIT 11 IS MOST SIGNIFICANT BIT.
CHARACTER COUNTER (THESE BITS AND KAD0--3 ARE USED TO COUNT THE CHARACTER TIMES FROM 0 TO 99 ON ANY LINE)
DECODE OF CHARACTER TIME 99 (THE END OF A SCAN l_INE). END BLANKING. ENABLE LOAD OF CHARACTER ADDRESS LATCH, RESETS
LAST LINE OF A TYPICAL ROW. OCCURS DURING LINE 9 ON 1920 CHARACTER D1'>PLAY AND LINE IS ON 960 CHARACTER DISPLAY. (CHARAc·rcR 99 TIMES)
LINc COUNTER OUTPUTS - RESET ro .ZERO A'T cND OF LINE (LCOL) OR AT END OP FRAME (ENDL).
LOADS CHARACTcR ADDRESS LATCH {KLQO·-KLQ7)
CLEARS CHARACTER ADDRESS LATCH (KLQO·KLQ7)
RESETS THE COMPOSITE SYNC FF UNDER THE CONTROL OF HDENDL OR HClEQSL
cNABLE VERTICAL BLANKING
VERTICAL BLANKING INTERVAL (EVER'< FRAME)
VERTICAL SYNC INTERVAL (EVERY Ffi•AME)
CHARACTER ADDRESS LATCH CONTAINS THC ADDRESS OF THE FIRST CHARACTER OF THE NEXT SCAN LINE. THE ADDRESS CHANGES DURING
THE LAST LINE OF EVERY ROW (AT HSQ TIME).
Figure 2-7. Timer Signal Relationships