Datasheet

18-16 MCF5407 User’s Manual
Misaligned Operands
transfer.
Figure 18-19. Longword Read from an 8-Bit Port, External Termination
Note that with external termination, address signals do not change. With internal
termination, Figure 18-20, A[1:0] increment for the same longword transfer.
Figure 18-20. Longword Read from an 8-Bit Port, Internal Termination
18.5 Misaligned Operands
Because operands, unlike opcodes, can reside at any byte boundary, they are allowed to be
misaligned. A byte operand is properly aligned at any address, a word operand is
misaligned at an odd address, and a longword is misaligned at an address not a multiple of
four. Although the MCF5407 enforces no alignment restrictions for data operands
(including program counter (PC) relative data addressing), additional bus cycles are
required for misaligned operands.
A[31:0], TT[1:0]
R/W
TIP
TS
AS, CSx
D[31:0]
TA
Read
Read
S0 S1 S2 S3 S4 S5 S10S9S8S7S6 S11 S12
Read
Read
CLKIN
BE
/BWEx, OE
TM[2:0], SIZ[1:0]
A[31:2], TT[1:0]
R/W
TIP
TS
AS, CSx
D[31:0]
TA
Read
Read
Read
Read
BE/BWEx, OE
TM[2:0], SIZ[1:0]
A[1:0]
S0 S1 S2 S3 S4 S5 S10S9S8S7S6 S11 S12
CLKIN