Datasheet

Bus Operation
6-70 MCF5206e USER’S MANUAL MOTOROLA
transfer, and the specific number of cycles needed for each transfer.
Figure 6-41. External Master Read Transfer using MCF5206e-Generated
Transfer Acknowledge Flowchart
EXTERNAL MASTER
MCF5206e
1. DRIVE ADDRESS ON A[27:0]
2. DRIVE R/W
TO READ (R/W = 1)
3. DRIVE SIZ[1:0] TO INDICATE BYTE,
WORD OR LONGWORD
4. ASSERT TS
FOR ONE CLK CYCLE
1. REGISTER EXTERNAL MASTER
A[27:0], R/W, SIZ[1:0]
1. NEGATE TS
1. REGISTER THE DATA
2. RECOGNIZE THE TRANSFER
IS DONE
1. DRIVE TA TO NEGATED STATE*
2. LOAD WAIT STATE COUNTER WITH
APPROPRIATE COUNT VALUE
1. DRIVE TA TO ASSERTED FOR
ONE CLK CYCLE
1. NEGATE TA FOR ONE CLK
CYCLE
1. DRIVE DATA ON THE
APPROPRIATE BYTE LANES
BASED ON SIZ[1:0], A[1:0] AND
PORT SIZE
SYSTEM
1. DECODE ADDRESS AND
SELECT THE APPROPRIATE
SLAVE DEVICE
1. THREE-STATE TA.
*TA IS DRIVEN NEGATED IF THE APPROPRIATE WAIT STATE COUNT IS GREATER THAN ZERO. IF THE WAIT STATE COUNT IS ZERO, TA
IS DRIVEN AND ASSERTED DURING THE SAME CLK
.
Fr
eescale S
emiconduct
or
, I
Freescale Semiconductor, Inc.
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