Commodore Amiga A500 - Page 48

PAL1 6R6
ARBITRATE
REV1
1 -6-86
AMlGA
7M /BRIN /RE /KIN /BR5 /BR4 /BR3 /BR2 /BR1 GND
GROUND
/BGOUT IBGOLD /BG5 /BG4 /K3 /BG2 /K1 /BR VCC
BG1 = BGIN * /%OLD * BR1 *
KIN* K1 *
BG2 = BGIN * IBGOLD * BR2 * /BR1 *
BGIN*BG2 *
/RE + ;GENERATE BG1
/RE ;HOLD UNTIL IBG
BG3 = KIN * IBGOLD * BR3 * /BR1 * /BR2 *
/RE +
BGIN * BG3 * /RE
BG5 = BGlN * IBGOLD * BR5 * /BR1 * /BR2 * /BR3 * /BR4 *
/RE +
BGIN*BG5 * /RE
BGOLD = KIN
;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