The keyboard protocol I envision, from the perspective of the Sentinel 65X CPU, is as follows:<li>Each time the latch line activates, reload the two-byte output buffer</li><li>Shift bits out MSB first</li><li>Bits shifted after 16 but without another latch will all be 1</li><li>The keyboard reports two bytes, which are always as follows, shfted low byte, high bit first.</li><code>; <br>; 76543210 First byte<br>; |+++++++- Keyboard scan code<br>; +-------- Ctrl key state (1: up; 0: down)<br>; <br>; 76543210 Second byte<br>; ||||++++- Signature: always 0011<br>; |||+----- Shift key state (1: up; 0: down)<br>; |+------- Option key state (1: up; 0: down)<br>; +-------- Command key state (1: up; 0: down)<br></code>
The modifier key state is captured at the time the latch activates.
Does this seem sane to you?
mos_8502 :verified: /
npub1qn…5hzwk
2024-06-13 16:48:27
in reply to nevent1q…88kd
Author Public Key
npub1qnufz4pycufk27kkeev5g0fgm0w0tqexsly674s2uwy0tynk5ymsk5hzwkPublished at
2024-06-13 16:48:27Event JSON
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"content": "The keyboard protocol I envision, from the perspective of the Sentinel 65X CPU, is as follows:\u003cli\u003eEach time the latch line activates, reload the two-byte output buffer\u003c/li\u003e\u003cli\u003eShift bits out MSB\u0026nbsp;first\u003c/li\u003e\u003cli\u003eBits shifted after 16 but without another latch will all be 1\u003c/li\u003e\u003cli\u003eThe keyboard reports two bytes, which are always as follows, shfted low byte, high bit first.\u003c/li\u003e\u003ccode\u003e; \u003cbr\u003e; 76543210 First byte\u003cbr\u003e; |+++++++- Keyboard scan code\u003cbr\u003e; +-------- Ctrl key state (1: up; 0: down)\u003cbr\u003e; \u003cbr\u003e; 76543210 Second byte\u003cbr\u003e; ||||++++- Signature: always 0011\u003cbr\u003e; |||+----- Shift key state (1: up; 0: down)\u003cbr\u003e; |+------- Option key state (1: up; 0: down)\u003cbr\u003e; +-------- Command key state (1: up; 0: down)\u003cbr\u003e\u003c/code\u003e\n\nThe modifier key state is captured at the time the latch activates.\n\nDoes this seem sane to you?",
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