MC68HC000RC12 Datasheet, PDF (48/189 Pages) Freescale Semiconductor, Inc – 8-/16-/32-Bit Microprocessors User’s Manual

Freescale Semiconductor, Inc.
BUS MASTER
ADDRESS THE DEVICE
1) SET R/W TO READ
2) PLACE FUNCTION CODE ON FC2–FC0
3) PLACE ADDRESS ON A23–A1
4) ASSERT ADDRESS STROBE (AS)
5) ASSERT UPPER DATA STROBE (UDS)
AND LOWER DATA STROBE (LDS)
ACQUIRE THE DATA
1) LATCH DATA
2) NEGATE UDS AND LDS
3) NEGATE AS
SLAVE
INPUT THE DATA
1) DECODE ADDRESS
2) PLACE DATA ON D15–D0
3) ASSERT DATA TRANSFER
ACKNOWLEDGE (DTACK)
TERMINATE THE CYCLE
1) REMOVE DATA FROM D15–D0
2) NEGATE DTACK
START NEXT CYCLE
Figure 5-1. Word Read-Cycle Flowchart
BUS MASTER
ADDRESS THE DEVICE
1) SET R/W TO READ
2) PLACE FUNCTION CODE ON FC2–FC0
3) PLACE ADDRESS ON A23-A1
4) ASSERT ADDRESS STROBE (AS)
5) ASSERT UPPER DATA STROBE (UDS)
OR LOWER DATA STROBE (LDS)
(BASED ON INTERNAL A0)
ACQUIRE THE DATA
1) LATCH DATA
2) NEGATE UDS AND LDS
3) NEGATE AS
START NEXT CYCLE
SLAVE
INPUT THE DATA
1) DECODE ADDRESS
2) PLACE DATA ON D7–D0 OR D15–D8
(BASED ON UDS OR LDS)
3) ASSERT DATA TRANSFER
ACKNOWLEDGE (DTACK)
TERMINATE THE CYCLE
1) REMOVE DATA FROM D7–D0
OR D15–D8
2) NEGATE DTACK
Figure 5-2. Byte Read-Cycle Flowchart
5-2
M68000 8-/16-/32-BIT MICROPROCESSORS USER'S MANUAL
MOTOROLA
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