Ckbuff LDA, Bkcksm LDA | Apple II specs

2647	F1D2				;CHCK ACTIVE BUFFER AND LOAD A CHR
2648	F1D2				;CARRY=0 IF ONLY 1 BUFFER ,C=1 IF 2 BUFFERS
2649	F1D2 AD 12 A4				CKBUFF LDA		INFLG
2650	F1D5 CD 13 A4					CMP	OUTFLG
2651	F1D8 D0 08					BNE	CBUFF1
2652	F1DA C9 54					CMP	#'T'	;SEE IF INFLG=OUTFLG = T
2653	F1DC D0 04					BNE	CBUFF1
2654	F1DE 38					SEC		;USE PAGE 1 FOR OUTPUT BUFFER
2655	F1DF B5 AD					LDA	TABUF2,X
2656	F1E1 60					RTS
2657	F1E2 18				CBUFF1 CLC			;USE SAME BUFFER FOR I/O
2658	F1E3 BD 16 01					LDA	TABUFF,X
2659	F1E6 60					RTS
2660	F1E7
2661	F1E7				;COMPUTE BLOCK CHECKSUM & PUT IT
2662	F1E7				;AT THE END OF ACTIVE BUFFER
2663	F1E7 A9 00				BKCKSM LDA		#0	;CLEAR BLK CKSUM LOCAT
2664	F1E9 8D 66 01					STA	TABUFF+80
2665	F1EC 8D 67 01					STA	TABUFF+81
2666	F1EF A2 4F					LDX	#79
2667	F1F1 20 D2 F1				BKCK1	JSR CKBUFF		;GET CHR FROM EITHER BUFFER
2668	F1F4 18					CLC
2669	F1F5 6D 66 01					ADC TABUFF+80		;ADD TO CKSUM
2670	F1F8 8D 66 01					STA	TABUFF+80
2671	F1FB 90 03					BCC	*+5
2672	F1FD EE 67 01					INC	TABUFF+81
2673	F200	CA				DEX
2674	F201	10	EE			BPL BKCK1		;DO THE WHOLE BUFFER
2675	F203	A2	50			LDX	#80
2676	F205	AD 66 01				LDA	TABUFF+80	;PUT CKSUM INTO RIGHT BUFFER
2677	F208	20	0F	F2		JSR	BKCK2
2678	F20B E8					INX
2679	F20C AD 67 01					LDA	TABUFF+81
2680	F20F 48				BKCK2	PHA		;OUTPUT A CHAR TO RIGHT BUFFER
2681	F210	20	D2	F1		JSR CKBUFF		;GET WHICH BUFFER
2682	F213	68				PLA
2683	F214	B0	04			BCS BKCK3		;BRNCH TO SECOND BUFFER
2684	F216	9D	16	01		STA	TABUFF,X
2685	F219	60				RTS
2686	F21A 95 AD				BKCK3	STA TABUF2,X		;TO PAG 1
2687	F21C 60					RTS
2688	F21D
2689	F21D				;SET TAPE (1 OR 2) FOR OUTPUT
2690	F21D 20 C0 F2				TAOSET JSR SETSPD			;SET UP SPEED (# OF HALF PULSES)
2691	F220	AD 35 A4				LDA TAPOUT		;OUTPUT FLG (TAPE 1 OR 2)
2692	F223	20	1C	EE		JSR TIOSET		;SET PB4 OR PB5 TO ZERO
2693	F226	A9	EC			LDA	#DATOUT+MOFF ;SET CA2=0 (DATA OUT)
2694	F228	8D	0C	A8		STA	PCR
2695	F22B A9 C0					LDA	#T1FR	;SET TIMER IN FREE RUNNING
2696	F22D 8D 0B A8					STA	ACR
2697	F230	A9	00			LDA	#00
2698	F232	8D	05	A8		STA	T1CH	;START TIMER T1
2699	F235	AE 09 A4				LDX	GAP	;OUTPUT 4*GAP SYN BYTES
2700	F238	A9	16		TAOS1	LDA	#$16	;SYN CHAR
2701	F23A 20 4A F2					JSR	OUTTAP	;TO TAPE
2702	F23D 20 4A F2					JSR	OUTTAP
2703	F240	20	4A	F2		JSR	OUTTAP
2704	F243	20	4A	F2		JSR	OUTTAP
2705	F246	CA				DEX
2706	F247	D0	EF			BNE	TAOS1
2707	F249	60				RTS
2708	F24A

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 Ckbuff LDA, Bkcksm LDA

Models: II

CKBUFF LDA

CMP

CMP

BKCKSM LDA

II specifications