Commodore Amiga A500 Technical Reference Manual page 44

TABLE 3-2
PAL16L8
STEERING150R17REV3
11-17-85
AMIGA
/SLVOUT RD /ASQ /ASQ90 COLLIS /BG /AS /BGACK /DMAIN GND
/OWN /AOE /UDS /BERR /DMAOUT /LDS /DBOE /RES /D2P VCC
DBOE = AS * /RD * /BERR +
UDS * RD * ASQ * /BERR +
LDS* RD* ASQ* /BERR
D2P = /DMAOUT * SLVOUT * RD +
DMAOUT * /SLVOUT * /RD + ;UPSTREAM WRITES DOWNSTREAM SLAVE
DMAOUT* SLVOUT
AOE = BGACK
/BG * /DMAOUT +
AS
ASQ90
DMAOUT = DMAIN + OWN
IF (/RES * COLLIS) BERR = VCC
DESCRIPTION
SLVOUT = SLAVEOUT,ASQ = AS DELAYED,ASQ90 = AS CLKD ON LOW EDGE OF 7M.
BG = BUS GRANT,OWN = LOCAL OWN
COLLIS = BUS COLLISION,AOE = ADDR OUTPUT EN,DOE = DATA OE
RES = RESET,D2P=DATAT0 PROCESSOR
UDS LDS PROTECT AGAINST RDMODIFYWRITE 3STF1GHT & BERR= /DOE
+
+
41
;DATA DRIVERS DURING WRITE CYCLE
;TURN ON DRIVERS LATE FOR RD
UDS AND LDS PROTECT RD MOD WR
;TO AVOID TRI STATE FIGHT
;DOWNSTREAM READS UPSTREAM SLAVE
;MASTER AND SLAVE ARE UPSTREAM
;AS KEEPS ADDR WHEN /BG DROPS
;ASQ90 MAINTAINS VALID ADDR ON
; LAST PROC CYCLE