iec_pull_data_release_atn_clk:

	;; 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 CI2PRA
	ora #BIT_CI2PRA_DAT_OUT         ; pull
	sta CI2PRA
	and #$FF - BIT_CI2PRA_CLK_OUT   ; release
	sta CI2PRA
	and #$FF - BIT_CI2PRA_ATN_OUT   ; release
	sta CI2PRA
	rts