Programmable Timer 8253/8254
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8254 / 8253 THE PROGRAMMABLE INTERVAL TIMER
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Transcript of Programmable Timer 8253/8254
![Page 1: Programmable Timer 8253/8254](https://reader034.fdocuments.in/reader034/viewer/2022050709/55ce65b0bb61eb401d8b46a0/html5/thumbnails/1.jpg)
8254 / 8253
THE PROGRAMMABLE INTERVAL TIMER
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8254 / 8253
• Programmable interval timer/counter
• Includes three independent 16-bit counters
• Has six modes of operation
• Operation:-– A 16-bit count is loaded on the counter and on
command it starts decrement– When the count reaches zero it generates a
pulse
![Page 3: Programmable Timer 8253/8254](https://reader034.fdocuments.in/reader034/viewer/2022050709/55ce65b0bb61eb401d8b46a0/html5/thumbnails/3.jpg)
8254 Block Diagram
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8254 Control Word Format
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Mode 0: Interrupt on Terminal Count
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Mode 1 : Programmable One-Shot
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Mode 2 : Rate Generator Clock
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Mode 3: Square Wave Generator
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Mode 4: Software Triggered Strobe
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Mode 5: Hardware Triggered Strobe
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Read-Back Command Format
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Status Byte