Commodore Amiga A500 Technical Reference Manual page 48

PAL1 6R6
ARBITRATE REV1
1 -6-86
AMlGA
7M /BRIN / R E / K I N /BR5 /BR4 /BR3 /BR2 /BR1 GND
GROUND /BGOUT IBGOLD /BG5 /BG4 / K 3 /BG2 / K 1 /BR VCC
BG1
=
BGIN
*
/%OLD
*
BR1
*
K I N * K 1
*
BG2
=
BGIN
*
IBGOLD
*
BR2
*
/BR1
*
BGIN*BG2
*
/ R E
+
;GENERATE BG1
/ R E ;HOLD UNTIL IBG
BG3
=
K I N
*
IBGOLD
*
BR3
*
/BR1
*
/BR2
*
/ R E
+
BGIN
*
BG3
*
/ R E
BG5
=
BGlN
*
IBGOLD
*
BR5
*
/BR1
*
/BR2
*
/BR3
*
/BR4
*
/ R E
+
BGIN*BG5
*
/ R E
BGOLD
=
K I N
;STORE OLD STATE OF BG
BR
=
BRIN
*
/RES
+
BR1
*
/RES
+
BR2
*
/RES
+
BR3
*
/RES
+
BR4
*
/RES
+
BR5
*
/RES
DESCRIPTION
;BR IS RQST TO 68K
BG1 IS HIGHEST PRIORITY