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- TITLE VIDEO SHIFT
- ; REGISTER HIGH SPEED.
- PATTERN 04.
- REVISION 01.
- AUTHOR CHRIS JAY.
- COMPANY MMI SANTA CLARA, CA.
- DATE 19 JUNE 1986.
-
- CHIP VIDEO PAL20X8
-
- CK /LD D0 D1 D2 D3 D4 D5 D6 D7 CURS GND
- /OE REV Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 /RST VCC
-
- EQUATIONS
-
- ;THE PAL20X8 HAS BEEN PROGRAMMED AS A VIDEO SHIFT REGISTER.
- ;A DOT PATTERN IS READ FROM A CHARACTER FONT MEMORY, AND STROBED
- ;INTO THE EIGHT REGISTERS, WHEN THE PARALLEL LOAD HAS TAKEN
- ;PLACE THE DATA MAY BE CLOCKED OUT IN SERIAL TO BE GATED WITH
- ;LINE AND FRAME SYNC SIGNALS TO FORM A COMPOSITE VIDEO OUTPUT.
- ;ATTRIBUTES AVAILABLE IN THE PAL DESIGN ARE; VIDEO, REVERSE VIDEO
- ;AND A CURSOR. THE STANDARD THAT HAS BEEN SET IS, LOGIC ZERO IS
- ;BLACK AND LOGIC HIGH IS ILLUMINATED. DURING THE SHIFT MODE DATA
- ;IS SHIFTED FROM THE MOST SIGNIFICANT REGISTER TO THE LEAST
- ;SIGNIFICANT REGISTER IN EIGHT CLOCK PULSES.
- ;THE TRUTH TABLE IS SHOWN BELOW.
- ;
- ;
- ;
- ; CLOCK /LD REV CURS /RST QN
- ; _______________________________________________
- ; | | | | | | |
- ; | CLK | L | L | L | H | DN |
- ; |_______|_______|_______|_______|_______|_______|
- ; | | | | | | |
- ; | CLK | L | H | L | H | /DN |
- ; |_______|_______|_______|_______|_______|_______|
- ; | | | | | | |
- ; | CLK | H | X | L | H | QN+1 |
- ; |_______|_______|_______|_______|_______|_______|
- ; | | | | | | |
- ; | CLK | X | X | H | H | HIGH |
- ; |_______|_______|_______|_______|_______|_______|
- ; | | | | | | |
- ; | CLK | X | X | X | L | LOW |
- ; |_______|_______|_______|_______|_______|_______|
- ;
- ;
- ;
- ;
-
- /Q0 := /D0*LD*/REV*/CURS*/RST ;LOAD D0
- + D0*LD*REV*/CURS*/RST ;LOAD INVERSE OF D0
- :+: /Q1*/LD*/CURS*/RST ;SHIFT FROM Q1
- + RST ;RESET Q0 LOW
- ;
- ;CURSOR LOW CLEARS /Q0
- /Q1 := /D1*LD*/REV*/CURS*/RST ;LOAD D1
- + D1*LD*REV*/CURS*/RST ;LOAD INVERSE OF D1
- :+: /Q2*/LD*/CURS*/RST ;SHIFT FROM Q2
- + RST ;CURSOR LOW CLEARS /Q1
- ;RESET CLEARS Q1
- /Q2 := /D2*LD*/REV*/CURS*/RST ;LOAD D2
- + D2*LD*REV*/CURS*/RST ;LOAD INVERSE OF D2
- :+: /Q3*/LD*/CURS*/RST ;SHIFT FROM Q3
- + RST ;CURSOR LOW CLEARS /Q2
- ;RESET CLEARS Q2
- /Q3 := /D3*LD*/REV*/CURS*/RST ;LOAD D3
- + D3*LD*REV*/CURS*/RST ;LOAD INVERSE OF D3
- :+: /Q4*/LD*/CURS*/RST ;SHIFT FROM Q4
- + RST ;RESET CLEARS Q3
- ;CURSOR LOW CLEARS /Q3
- /Q4 := /D4*LD*/REV*/CURS*/RST ;LOAD D4
- + D4*LD*REV*/CURS*/RST ;LOAD INVERSE OF D4
- :+: /Q5*/LD*/CURS*/RST ;SHIFT FROM Q5
- + RST ;CURSOR LOW CLEARS /Q4
- ;RESET CLEARS Q4
- /Q5 := /D5*LD*/REV*/CURS*/RST ;LOAD D5
- + D5*LD*REV*/CURS*/RST ;LOAD INVERSE OF D5
- :+: /Q6*/LD*/CURS*/RST ;SHIFT FROM Q6
- + RST ;CURSOR LOW CLEARS /Q5
- ;RESET CLEARS Q5
- /Q6 := /D6*LD*/REV*/CURS*/RST ;LOAD D6
- + D6*LD*REV*/CURS*/RST ;LOAD INVERSE OF D6
- :+: /Q7*/LD*/CURS*/RST ;SHIFT FROM Q7
- + RST ;CURSOR LOW CLEARS /Q6
- ;RESET CLEARS Q6
- /Q7 := /D7*LD*/REV*/CURS*/RST ;LOAD D7
- + D7*LD*REV*/CURS*/RST ;LOAD INVERSE OF D7
- :+: /LD*/CURS*/RST ;SHIFT HIGH INTO /Q7
- + RST ;RESET CLEARS Q7
- ;
-
- SIMULATION
-
- TRACE_ON D0 D1 D2 D3 D4 D5 D6 D7 CURS /RST
- REV CK /LD Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7
-
- SETF OE /CK ;ENABLE OUTPUTS
- SETF RST ;INITALISE ALL Q
- CLOCKF ;OUTPUTS TO ZERO
- SETF /RST ;SET RST INACTIVE
- SETF LD D0 /D1 D2 /D3 D4 /D5 D6 /D7 /CURS /REV ;LOAD ALTERNATING BIT
- CLOCKF CK ;PATTERN.
- SETF /LD ;SET INTO SHIFT MODE
- FOR I := 1 TO 8 DO ;AND SHIFT OUT 8 BITS.
- BEGIN ;
- CLOCKF ;
- END ;
- SETF LD REV ;SET REVERSE VIDEO AND
- CLOCKF ;LOAD SAME BIT PATTERN
- SETF /LD ;SET INTO SHIFT MODE
- FOR I := 1 TO 8 DO ;AND SHIFT OUT EIGHT
- BEGIN CLOCKF ;BITS
- END ;
- SETF CURS ;SET CURSOR ACTIVE
- FOR I := 1 TO 7 DO ;CLOCK OUT CURSOR
- BEGIN CLOCKF ;
- END ;
- TRACE_OFF
-