Intel mcs-48 manual Here the 8212 is used as the status latch for an 8080A

8212

VI. Output Port (With Hand-Shaking)

The 8212 can be used to transmit data from the data bus to a system output. The output strobe could be a hand- shaking signal such as "reception of data" from the device that the system is outputting to. It In turn, can interrupt the system signifying the reception of data. The selection of the port comes from the device selection logic.(OS1·OS2)

OUTPUT PORT (WITH HAND-SHAKING)

	DATA	r----....-
	BUS
			OUTPUT STROBE
		STB
			SYSTEM OUTPUT
			SYSTEM RESET
			PORT SELECTION
SYSTEM		L--'-'____-	} :~~~2~ONTROL)

INTERRUPT

VII. 808GA Status Latch

Here the 8212 is used as the status latch for an 8080A

microcomputer system. Tha input to the 8212 ;atch Is

directly from the 8080A data bus. Timing shows that when the SYNC signal is true, which is connected to the OS2 input and the phase 1 signal is true, which is a TTL level coming from the clock generator; then, the status data will be latched into the 8212.

Note: The mode signal Is tied high so thatthe output on the iatch is active and enabied aii the time.

It is shown that the two areas of concern are the bl- di rectional data bus ofthe microprocessor and the control bus.

/:0 3			3				DATA BUS
			10
		0 1	9
		O2	8
			7
		0
8080A		4	4
		0 5	5
		0 6	6
		0 7
	SYNC		19
	DBIN r!1-
\11		\12			STATUS
	22	15			LATCH
				--4		Do 4- INTA
12V"	l----,				0 1
ovJ ' -."""				~7		~ wo		11	T2
				9		rfu- STACK		~1
				16		r,s HLTA
				18	8212	P,t- OUr	BASIC
				20		ffg- Ml	CONTROL	¢2
CLOCK GEN.			~Tl)	22		rt"" INP	BUS
				r;1	CLR	r:- MEMR	SYNC
	Io DRIVER
					DS2 MD OS1
					13 12	'('1	DATA

DBIN

STATUS

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