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7d568bd782
Add _TRA!, _THA!, _TRB!, _THB! routines to easily handle those pins' value without stepping on other pins like the drivers previously did. For SDC driver, it's going to be important soon because it turns out that I can't get away with "always on" CS, so I'll need a scheme where it's important that TH/TR pins have stable values.
11 lines
377 B
Plaintext
11 lines
377 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 current bit to TRB, TR's output bit )
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DUP 7 I - RSHIFT 1 AND _TRB!
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1 _THB! ( CLK hi )
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0 _THB! ( CLK lo )
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( read into rx ) SWAP 1 LSHIFT _D1@ ( 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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