Bus Operation
MCF5253 Reference Manual, Rev. 1
Freescale Semiconductor
8-13
Figure 8-12. Line Write Burst with One Wait State
Figure 8-13. Line Write Burst-Inhibited
8.6
Misaligned Operands
All MCF5253 data formats can be located in memory on any byte boundary. 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 that is not evenly divisible by four. Unlike opcodes, because operands can reside at any byte
boundary, they are allowed to be misaligned. Although the MCF5253 does not enforce any alignment
restrictions for data operands (including program counter (PC) relative data addressing), some
performance degradation occurs when additional bus cycles are required for longword or word operands
that are misaligned. For maximum performance, data items should be aligned on their natural boundaries.
All instruction words and extension words (opcodes) must reside on word boundaries. An address error
exception will occur with any attempt to prefetch an instruction word at an odd address.
Summary of Contents for MCF5253
Page 1: ...Document Number MCF5253RM Rev 1 08 2008 MCF5253 Reference Manual...
Page 26: ...MCF5253 Reference Manual Rev 1 xxvi Freescale Semiconductor...
Page 32: ...MCF5253 Reference Manual Rev 1 xxxii Freescale Semiconductor...
Page 46: ...MCF5253 Introduction MCF5253 Reference Manual Rev 1 1 14 Freescale Semiconductor...
Page 62: ...Signal Description MCF5253 Reference Manual Rev 1 2 16 Freescale Semiconductor...
Page 98: ...Instruction Cache MCF5253 Reference Manual Rev 1 5 10 Freescale Semiconductor...
Page 104: ...Static RAM SRAM MCF5253 Reference Manual Rev 1 6 6 Freescale Semiconductor...
Page 128: ...Synchronous DRAM Controller Module MCF5253 Reference Manual Rev 1 7 24 Freescale Semiconductor...
Page 144: ...Bus Operation MCF5253 Reference Manual Rev 1 8 16 Freescale Semiconductor...
Page 176: ...System Integration Module SIM MCF5253 Reference Manual Rev 1 9 32 Freescale Semiconductor...
Page 198: ...Analog to Digital Converter ADC MCF5253 Reference Manual Rev 1 12 6 Freescale Semiconductor...
Page 246: ...DMA Controller MCF5253 Reference Manual Rev 1 14 18 Freescale Semiconductor...
Page 282: ...UART Modules MCF5253 Reference Manual Rev 1 15 36 Freescale Semiconductor...
Page 344: ...Audio Interface Module AIM MCF5253 Reference Manual Rev 1 17 46 Freescale Semiconductor...
Page 362: ...I2 C Modules MCF5253 Reference Manual Rev 1 18 18 Freescale Semiconductor...
Page 370: ...Boot ROM MCF5253 Reference Manual Rev 1 19 8 Freescale Semiconductor...