Input Devices - Milwaukee School of Engineering › ... › EE4980 › files4980 › input_devices.… · Input Devices •Keypad PT0 PT1 PT2 PT3 PT4 PT5 PT6 PT7 Port[0:3] = Inputs

Input Devices

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Input Devices

• Keypad

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Input Devices

• Keypad

PT0 PT1 PT2 PT3

PT4

PT5

PT6

PT7

Port[0:3] = InputsVdd

Port[7:4] = OutputsPull one of

PT4, PT5, PT6, PT7 low

If a key is pressedThe associated PT[3:0] inputwill be pulled low

Scanning:Cycle through the outputs, check the inputs

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Input Devices

• Keypad

PT0 PT1 PT2 PT3

PT4

PT5

PT6

PT7

Port[0:3] = Inputs with pull-up turned on

Port[7:4] = OutputsPull one of

PT4, PT5, PT6, PT7 low

If a key is pressedThe associated PT[3:0] inputwill be pulled low

Scanning:Cycle through the outputs, check the inputs

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Input Devices

• Keyboard

• N x M matrix of switches

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCL7X9t_CmsgCFYYWkgodGMsHbA&url=http://www.waitingforfriday.com/index.php/C64_VICE_Front-End&bvm=bv.103388427,d.aWw&psig=AFQjCNFjxcnLhKOV-Z3d4jkVDQC6n6ET7Q&ust=1443556875789014

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Input Devices

• Keyboard

• N x M matrix of switches

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCN6G15fDmsgCFQRCkgodYM0PLg&url=http://blog.wk.com/2013/04/04/wk-open-source-bridging-the-email-typingguitar-shredding-gap-using-technology/&bvm=bv.103388427,d.aWw&psig=AFQjCNFjxcnLhKOV-Z3d4jkVDQC6n6ET7Q&ust=1443556875789014

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Input Devices

• Keyboard

• Mechanical Switches

http://guides.obviously.com/cherry-mx-switches/22

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Input Devices

• Keyboard

• Mechanical Switches

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Input Devices

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCNexjNTFmsgCFRYSkgodP2QA4g&url=http://www.sun-rising.cn/ePRODUCT.asp&psig=AFQjCNFxqa4dY0l56SIvy_paKTryyvBmTQ&ust=1443557510978245

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Input Devices

• Keyboard• Controller

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Input Devices

• Keyboard

• Controller

• Performs debounce – 1-5ms typical

• Polling rate - < 200Hz

• Interface – USB, wireless, SPI, TWI

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Input Devices

• Mouse

• Opto-Mechanical

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Input Devices

• Mouse

• Opto-Mechanical

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Input Devices

• Mouse

• Opto-Mechanical

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Input Devices

• Mouse

• Opto-Mechanical

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Input Devices

• Mouse

• Optical Mouse

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Input Devices

• Mouse

• Optical Mouse

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Input Devices

• Mouse

• Optical Mouse Sensor

• By comparing images – direction and distance can be calculated

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Input Devices

• Mouse

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Input Devices

• Mouse

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Input Devices

• Mouse

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Input Devices

• Mouse


• Output is a quadrature signal - just like a mechanical mouse

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Input Devices

• Mouse


• Frame Rate: 1500 frames/sec

• Typical resolution: 400-800 cpi (counts/inch)

• Speed: 14ips (inches per second)

• Typical sensor dimension: 16x16 to 32x32

• Typical Path error: 0.5%

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Input Devices

• Mouse


• Limited focal range

Documents

Input Devices - Milwaukee School of Engineering › ... › EE4980 › files4980 › input_devices.… · Input Devices •Keypad PT0 PT1 PT2 PT3 PT4 PT5 PT6 PT7 Port[0:3] = Inputs