Ljxuh  1Rq0Dvndeoh ,Qwhuuxsw 5Htxhvw 2Shudwlrq - ZiLOG Z80 User Manual

< %27
7UGT U /CPWCN

A — A
15
MREQ
RFSH
+$/7 ([LW
80
Last M Cycle
Last T State
CLK
NMI
0
M1
RD

)LJXUH  1RQ0DVNDEOH ,QWHUUXSW 5HTXHVW 2SHUDWLRQ

:KHQHYHU D VRIWZDUH +$/7 LQVWUXFWLRQ LV H[HFXWHG WKH &38 H[HFXWHV
123V XQWLO DQ LQWHUUXSW LV UHFHLYHG HLWKHU D QRQPDVNDEOH RU D PDVNDEOH
LQWHUUXSW ZKLOH WKH LQWHUUXSW IOLSIORS LV HQDEOHG  7KH WZR LQWHUUXSW OLQHV
DUH VDPSOHG ZLWK WKH ULVLQJ FORFN HGJH GXULQJ HDFK 7 VWDWH DV GHSLFWHG LQ
)LJXUH  ,I D QRQPDVNDEOH LQWHUUXSW KDV EHHQ UHFHLYHG RU D PDVNDEOH
LQWHUUXSW KDV EHHQ UHFHLYHG DQG WKH LQWHUUXSW HQDEOH IOLSIORS LV VHW WKHQ WKH
+$/7 VWDWH LV H[LWHG RQ WKH QH[W ULVLQJ FORFN HGJH 7KH IROORZLQJ F\FOH LV
DQ LQWHUUXSW DFNQRZOHGJH F\FOH FRUUHVSRQGLQJ WR WKH W\SH RI LQWHUUXSW WKDW
ZDV UHFHLYHG ,I ERWK DUH UHFHLYHG DW WKLV WLPH WKHQ WKH QRQPDVNDEOH RQH
LV DFNQRZOHGJHG VLQFH LW KDV KLJKHVW SULRULW\ 7KH SXUSRVH RI H[HFXWLQJ
123 LQVWUXFWLRQV ZKLOH LQ WKH +$/7 VWDWH LV WR NHHS WKH PHPRU\ UHIUHVK
VLJQDOV DFWLYH (DFK F\FOH LQ WKH +$/7 VWDWH LV D QRUPDO 0 IHWFK F\FOH
H[FHSW WKDW WKH GDWD UHFHLYHG IURP WKH PHPRU\ LV LJQRUHG DQG D 123
LQVWUXFWLRQ LV IRUFHG LQWHUQDOO\ WR WKH &38 7KH +$/7 DFNQRZOHGJH VLJQDO
LV DFWLYH GXULQJ WKLV WLPH LQGLFDWLQJ WKDW WKH SURFHVVRU LV LQ WKH +$/7 VWDWH
M1
T
T T
1
2 3
PC
T
T
1
4
Refresh
2YHUYLHZ