mcf5407 Freescale Semiconductor, Inc, mcf5407 Datasheet - Page 440

• Manufacturer Part Number: mcf5407
• Description: Mcf5407 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

Data Transfer Operation
18.4.7.1 Line Transfers
A line is a 16-byte-aligned, 16-byte value. Despite the alignment, a line access may not
begin on the aligned address; therefore, the bus interface supports line transfers on multiple
address boundaries. Table 18-5 shows allowable patterns for line accesses.
18.4.7.2 Line Read Bus Cycles
Figure 18-12 shows line read with zero wait states. The access starts like a basic read bus
cycle with the first data transfer sampled on the rising edge of S4, but the next pipelined
burst data is sampled a cycle later on the rising edge of S6. Each subsequent pipelined data
burst is single cycle until the last one, which can be held for up to 2 CLKIN cycles after TA
is asserted. Note that AS and CSx are asserted throughout the burst transfer. This example
shows the timing for external termination, which differs only from the internal termination
example in Figure 18-13 in that the address lines change only at the beginning (assertion of
TS and TIP) and end (negation of TIP) of the transfer.
Figure 18-13 shows timing when internal termination is used.
18-12
TM[2:0], SIZ[1:0]
A[31:0], TT[1:0]
BE/BWEx, OE
AS, CSx
D[31:0]
CLKIN
R/W
TIP
TS
TA
Figure 18-12. Line Read Burst (2-1-1-1), External Termination
Table 18-5. Allowable Line Access Patterns
S0
A[3:2]
S1
00
01
10
11
S2
MCF5407 User’s Manual
S3
Read
S4
S5
Read
Longword Accesses
S6
0–4–8–C
4–8–C–0
8–C–0–4
C–0–4–8
Read
S7
S8
S9
Read
S10
S11 S12