Intel mcs-48 manual Signal Description, Mnemonic Description Bytes Cycles, Data Moves

8041 AJ8641AJ8741 A

PIN DESCRIPTION

Signal Description

00- 0 7 Three·state, bidirectional DATA BUS BUFFER lines

(BUS)	used to interface the UPI·41A to an 8·bit master
	system data bus.
P 10-P 17	8·bit, PORT 1 quasi·bidirectionall/O lines.

P20-P27 8·bit,PORT 2 quasi·bidirectionall/Olines. The lower

4bits (P20-P23)interface directly to the 8243 I/O ex· pander device and contain address and data infor· mation during PORT 4-7 access. The upper 4 bits

(P24-P27) can be programmed to provide Interrupt Request and DMA Handshake capability. Software

control can configure P24 as OBF (Output Buffer Full), P25 as IBF (Input Buffer Full~as DRQ (DMA Request), and P27 as DACK (DMA ACKnowledge).

WR	I/O write input which enables the master CPU to
	write data and command words to the UPI·41A IN·
	PUT DATA BUS BUFFER.
RD	110 read input which enables the master CPU to
	read data and status words from the OUTPUT DATA
	BUS BUFFER or status register.
CS	Chip select input used to select one UPI·41Aout of
	several connected to a common data bus.
Ao	Address input used by the master processor to in·
	dicate whether byte transfer is data or command.

TEST 0,	Input pins which can be directly tested using condi·
TEST 1	tional branch instructions.
	T1 also functions as the event timer input (under
	software control). To is used during PROM program·
	ming and verification in the 8741A.
XTAL 1,	Inputs for a crystal, LC or an external timing signal
XTAL2	to determine the internal oscillator frequency.
SYNC	Output signal which occurs once per UPI·41A in·
	struction cycle. SYNC can be used as a strobe for
	external circuitry; it is also used to synchronize
	single step operation.
EA	External access input which allows emulation,
	testing and PROM/ROM verification.
PROG	Multifunction pin used as the program pulse input
	during PROM programming.
	During I/O expander access the PROG pin acts as
	an address/data strobe to the 8243.
RESET	Input used to reset status flip·flops and to set the
	program counter to zero.
	RESET is also used during PROM programming and
	verification.

SSSingle step input used in the 8741A in conjunction with the SYNC output to step the program through each instruction.

Vee	+ 5V main power supply pin.
Voo	+ 5V during normal operation. + 25V during pro·
	gramming operation. Low power standby pin in
	ROM version.
Vss	Circuit ground potential.

UPITM INSTRUCTION SET

Mnemonic Description Bytes Cycles

ACCUMULATOR

ADD	A.Rr	Add register to A	1	1
ADD	A.@Rr	Add data memory to A	1	1
ADD A.#data		Add immediate to A	2	2
ADDC A.Rr		Add register to A with carry	1	1
ADDC A.@Rr		Add data memory to A with carry	1	1
ADDC Mdata		Add immed. to A with carry	2	2
ANL A.Rr		AND register to A	1	1
ANL A.@Rr		AND data memory to A	1	1
ANL A.#data		AND immediate to A	2	2
ORl A.Rr		OR register to A	1	1
ORL A.@Rr		OR data memory to A	1	1
ORL A.#data		OR immediate to A	2	2
XRl A.Rr		Exclusive OR register to A	1	1
XRL A.@Rr		Exclusive OR data memory to A	1	1
XRL A.#data		Exclusive OR immediate to A	2	2
INC A		Increment A	1	1
DEC A		Decrement A	1	1
CLR A		Clear A	1	1
CPL A		Complement A	1	1
DA A		Decimal Adjust A	1	1
SWAP A		Swap nibbles of A	1	1
RL A		Rotate A left	1	1
RlC A		Rotate A left through carry	1	1
RR A		Rotate A right	1
RRC A		Rotate A right through carry	1

INPUT/OUTPUT

IN A.Pp	Input port to A		2
OUTL Pp.A	Output A to port		2
ANl Pp.#data	AND Immediate to port		2
ORl Pp.#data	OR immediate to port		2
IN A.DBB	Input DBB to A. clear IBF		1
OUT DBB.A	Output A to DBB. set OBF		1
MOV STS,A	A4-A7 to Bits 4-7of Status		1
MOVD A.Pp	Input Expander port to A		2
MOVD Pp.A	Output A to Expander port		2
ANlD Pp.A	AND A to Expander port		2
ORlD Pp.A	OR A to Expander port		2
DATA MOVES
MOV A.Rr	Move register to A	1	1
MOV A.@Rr	Move data memory to A	1	1
MOV A.#data	Move Immediate to A	2	2
MOV Rr.A	Move A to register	1	1
MOV @Rr.A	Move A to data memory	1	1
MOV Rr.#data	Move immediate to register	2	2
MOV @Rr.#data	Move Immediate to data memory	2	2
MOV A.PSW	Move PSW to A	1	1
MOV PSW.A	Move A to PSW	1	1
XCH A.Rr	Exchange A and register	1	1
XCH A.@Rr	Exchange A and data memory	1	1
XCHD A.@Rr	Exchange digit of A and register	1	1
MOVP A.@A	Move to A from current page	1	2
MOVP3. A.@A	Move to A from page 3	1	2
TIMER/COUNTER
MOV A.T	Read Timer/Counter
MOV T.A	Load Timer /Counter
STRT T	Start Timer
STRT CNT	Start Counter
STOP TCNT	Stop Timer /Counter
EN TCNTI	Enable Timer /Counter Interrupt
DIS TCNTI	Disable Timer /Counter Interrupt

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