Z85233 Datasheet, PDF (273/317 Pages) Zilog, Inc. – The Zilog SCC Serial Communication Controller

Application Note
Technical Considerations When Implementing LocalTalk Link Access Protocol
APPENDIX A
Listing 1- Asembler Code for SCC Initialization
000001e2
000001e2 f3
000001e3 f5
000001e4 c5
000001e5 e5
000001e6 3e09
000001e8 d3e8
000001ea 3e80
000001ec d3e8
000001ee 00
000001ef 21Wwww
000001f2
000001f2 7e
000001f3 feff
000001f5 caWwww
000001f8 d3e8
000001fa 23
000001fb 7e
000001fc d3e8
000001fe 23
000001ff c3R000+01f2,
00000202
00000202 04
00000203 20
00000204 01
00000205 00
00000206 02
00000207 00
00000208 03
00000209 cc
0000020a 05
0000020b 60
0000020c 06
0000020d 00
0000020e 07
0000020f 7e
00000210 09
00000211 01
475
476
477
478 initscc:
479
di
480
push
481
push
482
push
483
484
ld
485
out
486
ld
487
out
488
nop
489
490
491
ld
492 scc1:
493
ld
494
cp
495
jp
496
out
497
inc
498
ld
499
out
500
inc
501
jp
502
503 scctable:
504
db
505
db
506
507
db
508
db
509
510
db
511
db
512
513
db
514
db
515
516
517
518
db
519
db
520
521
db
522
db
523
524
db
525
db
526
527
db
528
db
529
530
531
LISTING 1
af
bc
hl
a,09h
(scc_cont),a
a,80h
(scc_cont),a
;***************************************
;subroutine to initialize scc registers
;***************************************
;disable int while programming scc
;WR9
;point to scc register
;channel reset
;scc register value
;delay needed after scc reset
hl,scctable
a,(hl)
0ffh
z,finscc
(scc_cont),a
hl
a,(hl)
(scc_cont),a
hl
scc1
;fetch start of scc init table
;fetch register pointer value
;if reg a =0ffh then initscc finished
;loop back
04h
00100000b
01h
00h
02h
00h
03h
0cch
05h
60h
06h
00h
07h
7eh
09h
01h
;WR4
;sdlc uses 1x,sdlc mode,no parity
;WR1
;nothing,rx,tx and ext int disabled
;WR2
;vector base is 00h
;WR3
;rx 8b/char,rx crc enabled,address
;search mode for adlc address filtering
;rx disabled.
;WR5
;tx 8b/char, set rts to disable drivers
;WR6
;address field=’myaddress’ in main pgm
;WR7
;flag pattern
;WR9
;stat low, vis therefore vector returned
;is a variable depending on the source
;of the interrupt.
6-138
UM010901-0601