14 lines
391 B
ArmAsm
14 lines
391 B
ArmAsm
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iec_release_clk_pull_data:
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// Released CLK = DATA considered valid; for extra robustness on non-emulated
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// hardware give some lines few more cycles to stabilize; see page 10 of
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// http://www.zimmers.net/anonftp/pub/cbm/programming/serial-bus.pdf
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lda CIA2_PRA
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ora #BIT_CIA2_PRA_DAT_OUT // pull
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sta CIA2_PRA
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and #$FF - BIT_CIA2_PRA_CLK_OUT // release
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sta CIA2_PRA
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rts
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