
External Bus Interface
MOTOROLA
MPC801 USER’S MANUAL
13-17
13
Figure 13-11. Simplified Flow Diagram Of A Burst Read Cycle
MASTER
SLAVE
REQUEST BUS (BR)
RECEIVES BUS GRANT (BG) FROM ARBITER
ASSERTS BUS BUSY (BB) IF NO OTHER MASTER IS DRIVING
ASSERT TRANSFER START (TS)
DRIVES ADDRESS AND ATTRIBUTES
DRIVES BURST ASSERTED
RECEIVES ADDRESS
RETURNS DATA
ASSERTS TRANSFER ACKNOWLEDGE (TA)
RECEIVES DATA
ASSERT BURST DATA IN PROGRESS (BDIP)
BDIP ASSERTED
YES
RETURNS DATA
ASSERTS TRANSFER ACKNOWLEDGE (TA)
RECEIVES DATA
BDIP ASSERTED
YES
RETURNS DATA
ASSERTS TRANSFER ACKNOWLEDGE (TA)
RECEIVES DATA
BDIP ASSERTED
YES
RETURNS DATA
ASSERTS TRANSFER ACKNOWLEDGE (TA)
RECEIVES DATA
BDIP ASSERTED
YES
NEGATE BURST DATA IN PROGRESS (BDIP)
NO
DON’T DRIVE
DATA
NO
DON’T DRIVE
DATA
NO
DON’T DRIVE
DATA
NO
DON’T DRIVE
DATA