Intel mcs-48 manual Read, MIN. MAX Unit

8255A18255A·5

A.C. CHARACTERISTICS

TA = O°C to 70°C; Vcc = +5V ±5%; GND = OV

Bus Parameters

Read:

Write:

	I
SYMBOL	PARAMETER
tAW	Address Stable Before WR ITE
twA	Address Stable After WR ITE
tww	WRITE Pulse Width
tow	Data Valid to WR ITE (T.E.)
two	Data Valid After WR ITE

I	8255A	:~'
	MIN. MAX.			UNIT
	30	••• ns
	0			ns
	20			ns
	400	"~,100;i:"'~~" ;:		ns
	100	""'.. ,	:.".	ns
		"J:~", ..	'

Other Timings:
SYMBOL	PARAMETER
tws	WR = 1 to Outputl1 ]
tlR	Peripheral Data Before RD
tHR	Peripheral Data After RD
tAK	ACK Pulse Width
tST	STB Pulse Width
tps	Per. Data Before T.E. of STB
tpH	Per. Data After T.E. of STB
tAO	ACK = 0 to Outputl1 ]
tKO	ACK = 1 to Output Float
twos	WR = 1 to OBF = 011]
tAOS	ACK = 0 to OBF = 1111
tSIB	STB=OtoIBF=1[1]
tRIB	RD = 1 to IBF = 0[1]
tRIT	RD = Oto INTR = 0[1]
tSIT	STB = 1 to INTR = 1[1]
tAIT	ACK = 1 to INTR = 1[1]
tWIT	WR = Oto INTR = 011 ]

		~"i::J:,';:';;).:'\:;:,',:"':::.:,i'i·'•
	350	....MIN' ,"			ns
	8255A	.....	'~,'
MIN.	MAX.	.		...	UNIT
0		;'e)		i;'. ............... , ....	ns
0		f6>:'....			ns
180		Ft:r··...ns
300					ns
500		"'		,"	ns
0		,c· ,			ns
	300			~.'	ns
20	250	'20-		25(}	ns
	650			650	ns
	350			350	ns
	300			300	ns
	300			300	ns
	400			400	ns
	300			.300	ns
	350			.... 3S0 .	ns
				'
	850				ns

Not,.: 1. Test Conditions: 8255A: CL = loopF;8255A·5: CL = 150pF.

2.Period of Reset pulse must be at leest SOl'S during or after power on. Subsequent Reset pulse can be 500 ns min.

9-34 AFN-00744A-18