OUTTA1 PHA, OUTTA2 LDX | Apple II guide

2709	F24A				;OUTPUT ACC TO TAPE
2710	F24A 8E		2D	A4	OUTTAP STX CPIY+3			;SAVE X
2711	F24D A0		07			LDY #$07		;FOR THE 8 BITS
2712	F24F 8C		27	A4		STY	STIY
2713	F252	AE	08	A4		LDX	TSPEED
2714	F255	30	39			BMI OUTTA1		;IF ONE IS SUPER HIPER
2715	F257	48				PHA
2716	F258	A0	02		TRY	LDY	#2	;SEND 3 UNITS
2717	F25A 8C		28	A4		STY	STIY+1	;STARTING AT 3700 HZ
2718	F25D BE		0A	A4	ZON	LDX NPUL,Y		;#OF HALF CYCLES
2719	F260	48				PHA
2720	F261	B9	0B	A4	ZON1	LDA TIMG,Y		;SET UP LACTH FOR NEXT
2721	F264	8D	06	A8		STA T1LL		;PULSE (80 OR CA) (FREC)
2722	F267	A9	00			LDA	#0
2723	F269	8D	07	A8		STA	T1LH
2724	F26C 2C		0D	A8	ZON2	BIT	IFR	;WAIT FOR PREVIOUS
2725	F26F 50		FB			BVC	ZON2	;CYCLE (T1 INT FLG)
2726	F271	AD	04	A8		LDA T1L		;CLR INTERR FLG
2727	F274	CA				DEX
2728	F275	D0	EA			BNE ZON1		;SEND ALL CYCLES
2729	F277	68				PLA
2730	F278	CE	28	A4		DEC	STIY+1
2731	F27B F0		05			BEQ	SETZ	;BRCH IF LAST ONE
2732	F27D 30		07			BMI	ROUT	;BRCH IF NO MORE
2733	F27F 4A					LSR	A	;TAKE NEXT BIT
2734	F280	90	DB			BCC	ZON	;...IF IT'S A ONE...
2735	F282	A0	00		SETZ	LDY	#0	;SWITCH TO 2400 HZ
2736	F284	F0	D7			BEQ	ZON	;UNCONDITIONAL BRCH
2737	F286	CE	27	A4	ROUT	DEC	STIY	;ONE LESS BIT
2738	F289	10	CD			BPL TRY		;ANY MORE? GO BACK
2739	F28B 68				ROUT1	PLA		;RECOVER CHR
2740	F28C AE		2D	A4		LDX CPIY+3		;RESTORE X
2741	F28F 60					RTS
2742	F290
2743	F290				;OUTPUT HALF PULSE FOR			0 (1200 HZ) &
2744	F290				;TWO HALF PULSES FOR 1			(2400 HZ) (00 TSPEED)
2745	F290	48			OUTTA1 PHA
2746	F291	8D	28	A4		STA STIY+1		;STORE ACC
2747	F294	A2	02		OUTTA2 LDX		#2	;# OF HALF PULSES
2748	F296	A9	D0			LDA	#$D0	;1/2 PULSE OF 2400
2749	F298	8D	06	A8		STA	T1LL
2750	F29B A9		00			LDA	#00
2751	F29D 8D		07	A8		STA	T1LH
2752	F2A0 20		BC FF			JSR	PATC25	;WAIT TILL COMPLETED
2753	F2A3 4E		28	A4		LSR	STIY+1	;GET BITS FROM CHR
2754	F2A6 B0		0A			BCS	OUTTA3
2755	F2A8 A9		A0			LDA	#$A0	;BIT=0 ,OUTPUT 1200 HZ
2756	F2AA 8D		06	A8		STA	T1LL
2757	F2AD A9		01			LDA	#$01
2758	F2AF 8D		07	A8		STA	T1LH
2759	F2B2 20		BC FF		OUTTA3 JSR		PATC25
2760	F2B5 CA					DEX
2761	F2B6 10		FA			BPL OUTTA3		;OUTPUT 3 HALF PULSES
2762	F2B8 88					DEY
2763	F2B9 10		D9			BPL OUTTA2		;ALL BITS ?
2764	F2BB 4C		8B	F2		JMP ROUT1		;RESTORE REGS
2765	F2BE EA					NOP
2766	F2BF EA					NOP
2767	F2C0
2768	F2C0				;SET SPEED FROM NORMAL TO 3 TIMES NORMAL
2769	F2C0 AD		08	A4	SETSPD LDA TSPEED			;SPEED FLG
2770	F2C3 6A					ROR A		;NORMAL OR 3* NORM

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.