Motorola MC68030 User Manual

Bus Operation
7-32 MC68030 USER’S MANUAL MOTOROLA
Figure 7-19. Asynchronous Long-Word Read Cycle Flowchart
Figure 7-20. Asynchronous Byte Read Cycle Flowchart
CONTROLLER
ADDRESS DEVICE
1) ASSERT ECS/OCS FOR ONE-HALF CLOCK
2) SET R/W TO READ
3) DRIVE ADDRESS ON A31-A0
4) DRIVE FUNCTION CODE ON FC2-FC0
5) DRIVE SIZE (SIZ1-SIZ0) (FOUR BYTES)
6) CACHE INHIBIT OUT (CIOUT) BECOMES VALID
7) ASSERT ADDRESS STROBE (AS)
8) ASSERT DATA STROBE (DS)
9) ASSERT DATA BUFFER ENABLE (DBEN)
ACQUIRE DATA
2) LATCH DATA
3) NEGATE AS AND DS
4) NEGATE DBEN
START NEXT CYCLE
PRESENT DATA
1) DECODE ADDRESS
2) PLACE DATA ON D31-D0
3) ASSERT DATA TRANSFER AND SIZE
ACKNOWLEDGE (DSACKx)
TERMINATE CYCLE
1) REMOVE DATA FROM D31-D0
2) NEGATE DSACK
EXTERNAL DEVICE
1) SAMPLE CACHE IN (CIN)
START NEXT CYCLE
PRESENT DATA
1) DECODE ADDRESS
2) PLACE DATA ON D31-D324 OR
D23-D16 OR
D15-D8 OR
D7-D0
(BASED ON A1,A0, CACHE AND BUS WIDTH)
3) ASSERT DATA TRANSFER AND SIZE
ACKNOWLEDGE (DSACKx)
TERMINATE CYCLE
1) REMOVE DATA FROM D31-D0
2) NEGATE DSACK
EXTERNAL DEVICECONTROLLER
ADDRESS DEVICE
1) ASSERT ECS/OCS FOR ONE-HALF CLOCK
2) SET R/W TO READ
3) DRIVE ADDRESS ON A31-A0
4) DRIVE FUNCTION CODE ON FC2-FC0
5) DRIVE SIZE (SIZ1-SIZ0) (FOUR BYTES)
6) CACHE INHIBIT OUT (CIOUT) BECOMES VALID
7) ASSERT ADDRESS STROBE (AS)
8) ASSERT DATA STROBE (DS)
9) ASSERT DATA BUFFER ENABLE (DBEN)
ACQUIRE DATA
2) LATCH DATA
3) NEGATE AS AND DS
4) NEGATE DBEN
1)SAMPLE CACHE INHIBIT IN (CIIN)

Motorola MC68030 Specifications

General

Brand	Motorola
Model	MC68030
Category	Computer Hardware
Language	English