Zilog Z16C35 - Manual (Page 293)

Application Note
Technical Considerations When Implementing LocalTalk Link Access Protocol
14-5
1
784 ;subroutine to time out bit time 4.3 usec per bit
785 ;register c contains the number of bits to be
counted down
786 ;**********************************************
000002ef 787 bittime:
000002ef f5 788 push af ;save status and a reg
000002f0 c5 789 push bc ;save
000002f1 e5 790 push hl ;save
791 ;
000002f2 3ed2 792 ld a,0d2h ;ctc1 int vector
000002f4 d3e5 793 out (ctc1_cont),a
794
000002f6 3edf 795 ld a,11011111b ;
000002f8 d3e5 796 out (ctc1_cont),a ;enable int
797 ;select counter mode
798 ;clk/trg edge starts with rising edg
799 ;time constant follows
800 ;software reset
000002fa 79 801 ld a,c ;reg c contains the number of bits
000002fb d3e5 802 out (ctc1_cont),a ;load the number of bits to be counted
803 ;**
000002fd e1 804 pop hl ;restore
000002fe c1 805 pop bc ;restore
000002ff f1 806 pop af ;restate status and a reg
00000300 fb 807 ei
00000301 c9 808 ret
809
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