Intel mcs-48 manual Prog POO-P07, Vth, Reset Avss, Varef ANO,AN1 ALE Xtal, Stand Alone

8022

PIN DESCRIPTION

~rru[§I!..OIMlOIM~rruw

Designation

Vss

Vee

PROG

POO-P07

Port 0

VTH

P10-P17

Port 1

P20-P27

Port 2

TO

T1

Pin # Function.

20 Circuit GND p6tential.

40 + 5V circuit power supply.

37Output strobe for Intel@ 8243 II 0 expander.

10-17 8-bit open-drain port with qoin- parator inputs. The switching threshold is set externally by VTH. Optional pull-up resistors may be added via ROM mask selection.

9Port 0 threshold reference pin. 25-32 8-bit quasi-bidirectional port.

33-36 8-bit quasi-bidirectional port.

38-39 P20-23 also serve as a 4-bit 1-2 1/0 expander for Intel@ 8243.

8Interrupt input and input pin testable using the conditional transfer instructions JTO and JNTO. Initiates an interrupt fol- lowing a low level input if inter- rupt is enabled. Interrupt is disabled after a reset.

19Input pin testable using the JT1 and JNT 1 conditional transfer instructions. Can be designat- ed the timer I event counter in- put using the STRT CNT instruction. Also serves as the zero-cross detection input to allow zero-crossover sensing of slowly moving AC inputs. Op- tional pull-up resistor may be added via ROM mask selection.

Designation

RESET

AVSS

AVee

SUeST

VAREF

ANO,AN1

ALE

XTAL 1

XTAL 2

Pin # Function

24Input used to initialize the proc- essor by clearing status flip- flops and setting the program counter to zero.

7AID converter GND Potential. Also establishes the lower limit of the conversion range.

3 AID + 5V power supply.

21Substrate pin used with a by- pass capacitor to stabilize the substrate voltage and improve AID accuracy.

4A I D converter reference volt- age. Establishes the upper limit of the conversion range.

6,5 Analog inputs to AID converter. Software selectable on-chip via SEL ANO and SEL AN 1 instructions.

18Address Latch Enable. Signal occurring once every 30 input clocks (once every cycle), used as an output clock.

22One side of crystal or inductor input for internal oscillator. Also input for external frequency source. (Not TTL compatible.)

23Other side of timing control ele- ment. This pin is not connected when an external frequency source is used.

THE STAND ALONE 8022

		PI.	2.
		P11	25
			27
	V.,..,	P12
			28..
	AVec	PI'
10-2oo,u.F
	AV..
	2.
	Vaa
l00pF	I,F	8..2
SILVER MICA
		P2'
	SUBST		.8
		P••
			••
	AND	P••
AID INPUTS {		P26
		P27
	ANI	VTN
			I .
		PDO
	XTAL1		11
		POI
			12
		PO>
1M			,.
		P03
			13
	XTAL2	PDO	,.

PO!

T1

NC

}-,

}-. }-.

[ INPUT ]

AND

OUTPUT

[ WPUT ]

'AND

OUTPUT

[ INPUT ]

AND

. OUTPUT

6-52 AFN.(J()187A-QZ