Z85230 Datasheet, PDF (114/120 Pages) Zilog, Inc. – ENHANCED SERIAL COMMUNICATIONS CONTROLLER

==
(QKDQFHG 6HULDO &RPPXQLFDWLRQV &RQWUROOHU

GHWHFWLQJ WKH ODVW ELW RI WKH FORVLQJ IODJ DW WKH IDOOLQJ HGJH RI 7[& 7KLV IHDWXUH
GRHV QRW ZRUN LI EDFNWREDFN IUDPHV DUH VHQW 7KH 7[' RXWSXW LV DXWRPDWLFDOO\
IRUFHG +LJK IRU HLJKW ELWWLPHV DQG WKH ILUVW E\WH RI WKH VHFRQG IUDPH LV FRUUXSWHG
,Q D PXOWLSOHIUDPH WUDQVPLVVLRQ D ]HUR  ELW LV LQVHUWHG EHIRUH WKH RSHQLQJ IODJ
RI WKH VHFRQG IUDPH
$XWRPDWLF 7[' )RUFHG +LJK 3UREOHP 6ROXWLRQV
6HQG EDFNWREDFN IUDPHV LQ )/$* ,'/( PRGH EHFDXVH WKH $XWRPDWLF 7['
)RUFHG +LJK IHDWXUH FUHDWHV SUREOHPV RQO\ LI DOO WKH IROORZLQJ FRQGLWLRQV DUH WUXH
‡ %DFNWREDFN IUDPH WUDQVPLVVLRQ
‡ 15=,
‡ 0DUN ,GOH
6HWWLQJ WKH V\VWHP LQ )ODJ ,GOH PRGH :5 ELW  HTXDOV  LQ IUDPH WUDQVPLVVLRQ
DOORZV EDFNWREDFN IUDPHV WR EH VHQW ZLWKRXW DQ\ GDWD FRUUXSWLRQ
6'/& ),)2 2YHUIORZ 3UREOHP 'HVFULSWLRQ
,Q 6'/& PRGH ELW  RI 55 ),)2 2YHUIORZ VWDWXV ELW LV VHW LI DQ WK IUDPH HQGV
ZKLOH WKH ),)2 LV IXOO WKDW LV  IUDPHV KDYH DFFXPXODWHG LQ WKH 6WDWXV ),)2 DQG
KDYH QRW \HW EHHQ UHDG E\ WKH SURFHVVRU 8QGHU WKLV FLUFXPVWDQFH WKH VWDWXV
),)2 LV ORFNHG DQG QR GDWD FDQ EH ZULWWHQ WR WKH 6WDWXV ),)2 XQWLO ELW  RI 55 LV
UHVHW
,I WKH (6&& LV VHW XS LQ $17,/2&. PRGH WKDW LV WKH 6'.& ),)2 LV XVHG ZKHQ
5HFHLYH ,QWHUUXSWV RQ 6SHFLDO &RQGLWLRQ 2QO\ LV HQDEOHG WKH RQO\ PHWKRG RI UHVHW
WLQJ ELW  RI 55WKH ),)2 2YHUIORZ ELW LV WR UHVHW DQG VHW :5 ELW  6'/&
),)2 (QDEOH %LW 7KLV DFWLRQ FDXVHV WKH 6'/& ),)2 WR UHVHW DQG DOO WKH 6'/&
IUDPH LQIRUPDWLRQ LV ORVW
:LWK QR $QWL/RFN IHDWXUH WKH ),)2 2YHUIORZ VWDWXV ELW LV UHVHW LI WKH 6'/& ),)2
LV UHDG
,I WKH (6&& LV LQ 15=, DQG 0DUN ,GOH LQ EDFNWREDFN IUDPH WUDQVPLVVLRQ RQH WKH
),)2 2YHUIORZ ELW 55 ELW  LV VHW WKH RQO\ PHWKRG RI UHVHWWLQJ WKH VWDWXV LV WR
UHVHW DQG VHW :5 ELW  7KLV DFWLRQ FDXVHV WKH 6'/& ),)2 WR UHVHW DQG WKH
XQSURFHVVHG IUDPH LQIRUPDWLRQ VWRUHG LQ WKH 6'/& ),)2 LV ORVW
6'/& ),)2 2YHUIORZ 3UREOHP 6ROXWLRQV
'R QRW XVH 5HFHLYH ,QWHUUXSWV RQ 6SHFLDO &RQGLWLRQV 2QO\ DQG 0DUN ,GOH LI WKHUH LV
D SRVVLELOLW\ RI 6WDWXV ),)2 2YHUIORZ
36
== (UUDWD