External Bus Interface
MPC561/MPC563 Reference Manual, Rev. 1.2
9-30
Freescale Semiconductor
•
Word accesses require address bits 30 – 31 to equal zero
•
Burst accesses require address bits 30 – 31 to equal zero
The MPC561/MPC563 performs operand transfers through its 32-bit data port. If the transfer is controlled
by the internal memory controller, the MPC561/MPC563 can support 8- and 16-bit data port sizes.
The bus requires that the portion of the data bus used for a transfer to or from a particular port size be fixed.
A 32-bit port resides on DATA[0:31], a 16-bit port must reside on DATA[0:15], and an 8-bit port must
reside on DATA[0:7]. The MPC561/MPC563 always tries to transfer the maximum amount of data on all
bus cycles. For a word operation, it always assumes that the port is 32 bits wide when beginning the bus
cycle.
, the following conventions are used:
•
OP0 is the most-significant byte of a word operand and OP3 is the least-significant byte.
•
The two bytes of a half-word operand are either OP0 (most-significant) and OP1 or OP2
(most-significant) and OP3, depending on the address of the access.
•
The single byte of a byte-length operand is OP0, OP1, OP2, or OP3, depending on the address of
the access.
Figure 9-22. Internal Operand Representation
OP0
OP1
OP2
0
31
Word
Half-word
Byte
OP0
OP1
OP2
OP3
OP0
OP1
OP2
OP3
OP3
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...