13 lines
528 B
Plaintext
13 lines
528 B
Plaintext
: (spie) DROP ; ( always enabled )
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: (spix) ( x -- x, for port B )
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0 SWAP ( rx tx ) 8 0 DO
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( send bit 7 to bit 6, TR's output bit )
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DUP 1 RSHIFT 0x40 AND ( rx tx bits ) 0x80 OR ( CLK hi )
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0x3f PC@ OR 0xf3 AND ( TH and TR output )
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DUP 0x3f PC! ( rx tx bits )
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( CLK low ) 0x7f AND 0x3f PC! ( rx tx )
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( shift tx ) 1 LSHIFT ( rx tx<< )
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( read into rx ) SWAP 1 LSHIFT 0xdc PC@ ( tx<< rx<< x )
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( out bit is the 6th ) 6 RSHIFT 1 AND OR
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SWAP LOOP ( rx tx ) DROP ;
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