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