8085 MICROPROCESSOR
FEATURE OF 8085
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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scanned keyboard special error mode
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scanned keyboard with N-key rollover
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scanned keyboard mode with 2 key lockout
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sensor matrix mode
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Detailed explanation-1: -Explanation: In scanned keyboard mode with 2 key lockout mode of operation, when a key is pressed, a debounce logic comes into operation. During the next two scans, other keys are checked for closure and if no other key is pressed then the first pressed key is identified.
Detailed explanation-2: -In the 2-key lockout mode, if two keys are pressed simultaneously, only the first key is recognized. In the N-key rollover mode, simultaneous keys are recognized and their codes are stored in FIFO. The keyboard section also has an 8 x 8 FIFO (First In First Out) RAM.
Detailed explanation-3: -SCAN SECTION: In encoded scan mode, the output of scan lines will be binary count, and so an external decoder should be used to convert the binary count to decoded output. The scan lines are common for keyboard and display.
Detailed explanation-4: -The control and timing registers store the keyboard and display modes and other operations programmed by CPU.
Detailed explanation-5: -The scan lines are common for keyboard and display. The scan lines are used to form the rows of a matrix keyboard and also connected to digit drivers of a multiplexed display, to turn ON/OFF. CPU interface section: • The CPU interface section takes care of data transfer between 8279 and the processor.