Dftxfr LDX, Newdev LDA | Apple II instruction

1481	8B2D AD 02 A4					LDA	PBDA
1482	8B30	0A				ASL	A
1483	8B31	60				RTS
1484	8B32	AE 50 A6			PAD	LDX PADBIT		;PAD CARRIAGE RETURN OR LF
1485	8B35	20	E6	8A	PAD1	JSR DLYF		;WITH EXTRA STOP BITS
1486	8B38	CA				DEX
1487	8B39	D0	FA			BNE	PAD1
1488	8B3B 60					RTS
1489	8B3C 20 A3 89				TSTAT	JSR KSCONF		;SEE IF BREAK KEY DOWN
1490	8B3F AD 02 A4					LDA	PBDA
1491	8B42	2D	54	A6		AND	TOUTFL
1492	8B45	38				SEC
1493	8B46	E9	40			SBC	#$40
1494	8B48	60				RTS
1495	8B49	FF				.DB $FF		;NOT USED
1496	8B4A				; ***
1497	8B4A				; *** RESET - TURN OFF POR, INIT SYS RAM, ENTER MONITOR
1498	8B4A				; ***
1499	8B4A				;
1500	8B4A A2 FF				RESET	LDX	#$FF
1501	8B4C 9A					TXS		;INIT STACK PTR
1502	8B4D A9 CC					LDA	#$CC
1503	8B4F 8D 0C A0					STA	PCR1	;DISABLE POR, TAPE OFF
1504	8B52	A9	04			LDA	#4
1505	8B54	48				PHA
1506	8B55	28				PLP		;INIT F, DISABLE IRQ DURING DFTXFR
1507	8B56	20	86	8B		JSR	ACCESS	;UN WRITE PROT SYS RAM
1508	8B59	A2	5F		DFTXFR LDX		#$5F	;INIT SYS RAM (EXCPT SCPBUF)
1509	8B5B BD A0 8F					LDA	DFTBLK,X
1510	8B5E 9D 20 A6					STA	RAM,X
1511	8B61	CA				DEX
1512	8B62	10	F7			BPL	DFTXFR+2
1513	8B64	A9	07		NEWDEV LDA		#7	;CHANGE DEVC/BAUD RATE
1514	8B66	20	47	8A		JSR	OUTCHR	;BEEP
1515	8B69	20	A3	89	SWITCH JSR		KSCONF	;KEYBOARD OR TERMINAL?
1516	8B6C 20 26 89				SWLP	JSR	KEYQ+3
1517	8B6F D0 0B					BNE	MONENT
1518	8B71	2C	02	A4		BIT	PBDA
1519	8B74	10	F6			BPL	SWLP
1520	8B76	20	B7	8B		JSR	VECSW	;SWITCH VECTORS
1521	8B79	20	FF 8A			JSR	BAUD
1522	8B7C A2 FF				MONENT LDX #$FF			;MONITOR ENTRY
1523	8B7E 9A					TXS
1524	8B7F D8					CLD
1525	8B80	20	86	8B		JSR ACCESS		;UNWRITE PROT MONITOR RAM
1526	8B83	4C	03	80		JMP	WARM
1527	8B86	20	88	81	ACCESS JSR		SAVER	;UN WRITE PROT SYS RAM
1528	8B89	AD 01 AC				LDA	OR3A
1529	8B8C 09 01					ORA	#1
1530	8B8E 8D 01 AC				ACC1	STA	OR3A
1531	8B91	AD 03 AC				LDA	DDR3A
1532	8B94	09	01			ORA	#1
1533	8B96	8D	03	AC		STA	DDR3A
1534	8B99	4C	C4	81		JMP	RESALL
1535	8B9C 20 88 81				NACCES JSR		SAVER	;WRITE PROT SYS RAM
1536	8B9F AD 01 AC					LDA	OR3A
1537	8BA2 29 FE					AND	#$FE
1538	8BA4 18					CLC
1539	8BA5 90 E7					BCC	ACC1
1540	8BA7 20 86 8B				TTY	JSR	ACCESS	;UN WRITE PROT RAM
1541	8BAA A9 D5					LDA	#$D5	;110 BAUD
1542	8BAC 8D 51 A6					STA	SDBYT

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 Dftxfr LDX, Newdev LDA

Models: II

DFTXFR LDX

NEWDEV LDA

ORA

ORA

II specifications