LDA First Chip Select | Apple II specs

2337	EF81 A9		04			LDA	#4	;FIRST CHIP SELECT
2338	EF83 E0		00			CPX	#0	;FIRST CHIP ?
2339	EF85 F0		04			BEQ	OUTDD3
2340	EF87 0A				OUTDD2 ASL		A
2341	EF88 CA					DEX
2342	EF89 D0		FC			BNE OUTDD2		;BACK TILL RIGH CS
2343	EF8B 8D		28	A4	OUTDD3 STA STIY+1			;SAVE CS TEMPORARILY
2344	EF8E 68					PLA		;GET X AGAIN FOR CHAR
2345	EF8F 29		03			AND	#$03	;IN THAT CHIP
2346	EF91 0D		28	A4		ORA	STIY+1	;OR IN CS AND CHAR
2347	EF94				;STORE ADDR AND DATA INTO DISPL
2348	EF94 49		FF			EOR #$FF		;W=1 , CE=0 & A1,A0
2349	EF96 8D		00	AC		STA	RA
2350	EF99 AA					TAX		;SAVE A IN X
2351	EF9A 68					PLA		;GET DATA
2352	EF9B 48					PHA
2353	EF9C 8D		02	AC		STA	RB
2354	EF9F 8A					TXA
2355	EFA0 49		80			EOR #$80		;SET W=0
2356	EFA2 8D		00	AC		STA	RA
2357	EFA5 EA					NOP
2358	EFA6 09		7C			ORA #$7C		;SET CE=1
2359	EFA8 8D		00	AC		STA	RA
2360	EFAB A9		FF			LDA	#$FF	;SET W=1
2361	EFAD 8D		00	AC		STA	RA
2362	EFB0 68					PLA		;RETURN DATA
2363	EFB1 60					RTS
2364	EFB2
2365	EFF9					*=$EFF9
2366	EFF9 EA					.DB	$EA
2367	F000					*=$F000
2368	F000				;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
2369	F000				;OUTPUT ACC TO PRINTER SUBROUTINE
2370	F000				;PRINTS ON		21RST CHAR OR WHEN <CR>
2371	F000				;IT WILL PUT IT ON BUBFFER BUT WONT PRINT IF
2372	F000				;PRIFLG=0
2373	F000	48			OUTPRI PHA			;SAVE CHR TO BE OUTPUT
2374	F001	20	9E	EB		JSR	PHXY	;SAVE X
2375	F004	C9	0D			CMP	#CR	;SEE IF CR
2376	F006	F0	07			BEQ	OUT01	;YES SO PRINT THE BUFF
2377	F008	AE	16	A4		LDX	CURPOS	;PTR TO NEXT POS IN BUFF
2378	F00B E0		14			CPX	#20	;SEE IF BUFF FULL
2379	F00D D0		16			BNE OUT04		;NOT FULL SO RETURN
2380	F00F				;<CR> SO FILL REST OF BUFFER WITH BLANKS
2381	F00F 48				OUT01	PHA
2382	F010	A9	00			LDA	#0	;CURPOS = 0
2383	F012	AE	16	A4		LDX	CURPOS	;SEE IF ANYTHING IN BUFFER
2384	F015	8D	16	A4		STA	CURPOS
2385	F018	20	38	F0		JSR OUTPR		;CLEAR PRIBUF TO THE RIGHT
2386	F01B				;BUFFER FILLED SO PRINT IT
2387	F01B 20		45	F0		JSR IPST		;START THE PRINT
2388	F01E A2		00			LDX	#0	;STORE CHR IN BUFF (FIRST LOC)
2389	F020	68				PLA		;GET IT
2390	F021	C9	0D			CMP	#CR	;DONT STORE IF <CR>
2391	F023	F0	0E			BEQ	OUT05
2392	F025	9D	60	A4	OUT04	STA	IBUFM,X	;STORE CHR IN BUFF
2393	F028	EE	16	A4		INC CURPOS		;INCR BUFF PNTR
2394	F02B E8					INX
2395	F02C 29		80			AND	#$80
2396	F02E D0		03			BNE	OUT05	;DONT CLR IF MSB=1
2397	F030	20	38	F0		JSR	OUTPR	;CLEAR PRIBUFF TO THE RIGHT
2398	F033	20	AC EB		OUT05	JSR	PLXY	;RESTORE REGS

II specifications

The Apple II, launched in April 1977, was one of the first highly successful mass-produced microcomputer products. It marked a significant leap in personal computing, setting standards for future developments in the industry. Created by Steve Wozniak and Steve Jobs, the Apple II differentiated itself with its user-friendly design, appealing aesthetics, and robust capabilities.

One of the standout features of the Apple II was its open architecture, which allowed users to expand and enhance the computer's functionality. This design enabled hundreds of third-party hardware and software developers to contribute to its ecosystem, resulting in an array of peripherals, including printers, modems, and storage devices. The Apple II utilized a MOS Technology 6502 microprocessor running at a clock speed of 1 MHz. Initially equipped with 4 KB of RAM, the machine could be expanded to 48 KB, accommodating more complex applications and programs.

The Apple II was also notable for its colorful graphics. It was one of the first computers to support color display, offering a 6-color palette with a resolution of 280x192 pixels in 16 colors when using its Color Graphics Card. This feature significantly enhanced the visual appeal of games and educational software developed for the platform, making computing more accessible and entertaining for various audiences.

Apple's commitment to user experience was evident in the design of the machine. It featured an integrated keyboard and a plastic case, which was both durable and visually appealing. The self-contained design included drive bays for floppy disk drives, allowing for quicker data access than traditional tape drives. It also supported audio output, enabling sound effects and music, a novelty at the time.

The introduction of the Apple DOS operating system further underscored the machine's capabilities. DOS streamlined file management and made it easier for users to navigate and manage their data. The combination of hardware and software positioned the Apple II as an educational tool and a gaming platform, fostering a vibrant software ecosystem.

The Apple II family continued to evolve, with variations like the Apple II+, IIe, and IIgs being introduced over the years. These iterations brought enhancements in memory, processing power, and graphics capabilities. The legacy of the Apple II endures, not only as a foundational product in personal computing but also as a symbol of innovation that paved the way for future advancements in technology. Its impact is still felt today, as it inspired countless developers and shaped the trajectory of the computer industry.

Apple II manual LDA First Chip Select

Models: II

LDA

;FIRST CHIP SELECT

ORA

TAX

TXA

CMP

CMP

II specifications