MOTOROLA
Chapter 12. Chip Select Module
12-3
Chip Select Operation
12.3 Chip Select Operation
Each chip select has a dedicated set of registers for configuration and control.
• Chip select address registers (CSAR
n
) control the base address of the chip select.
See Section 12.4.1.1.
• Chip select mask registers (CSMR
n
) provide 16-bit address masking and access
control. See Section 12.4.1.2.
• Chip select control registers (CSCR
n
) provide port size and burst capability
indication, wait-state generation, and automatic acknowledge generation features.
See Section 12.4.1.3.
CS0 is a global chip select after reset and provides relocatable boot ROM capability.
12.3.1 General Chip Select Operation
When a bus cycle is initiated, the MCF5282 first compares its address with the base address
and mask configurations programmed for chip selects 0–6 (configured in CSCR0–CSCR6)
and DRAM blocks 0 and 1 (configured in DACR0 and DACR1). If the driven address
matches a programmed chip select or DRAM block, the appropriate chip select is asserted
or the DRAM block is selected using the specifications programmed in the respective
configuration register. Otherwise, the following occurs:
• If the address and attributes do not match in CSAR or DACR, the MCF5282 runs an
external burst-inhibited bus cycle with a default of external termination on a 32-bit
port.
• Should an address and attribute match in multiple CSCRs, the matching chip select
signals are driven; however, the chip select signals are driven during an external
burst-inhibited bus cycle with external termination on a 32-bit port.
• If the address and attribute match both DACRs or a DACR and a CSAR, the
operation is undefined.
Table 12-3 shows the type of access as a function of match in the CSARs and DACRs.
Summary of Contents for ColdFire MCF5281
Page 124: ...3 20 MCF5282 User s Manual MOTOROLA EMAC Instruction Set Summary ...
Page 141: ...MOTOROLA Chapter 5 Static RAM SRAM 5 5 SRAM Programming Model ...
Page 142: ...5 6 MCF5282 User s Manual MOTOROLA SRAM Programming Model ...
Page 168: ...6 26 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 186: ...7 18 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 228: ...9 22 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 246: ...10 18 MCF5282 User s Manual MOTOROLA Low Power Wakeup Operation ...
Page 254: ...11 8 MCF5282 User s Manual MOTOROLA Memory Map and Registers ...
Page 264: ...12 10 MCF5282 User s Manual MOTOROLA Chip Select Registers ...
Page 280: ...13 16 MCF5282 User s Manual MOTOROLA Misaligned Operands ...
Page 314: ...14 34 MCF5282 User s Manual MOTOROLA MCF5282 External Signals ...
Page 339: ...MOTOROLA Chapter 15 Synchronous DRAM Controller Module 15 25 SDRAM Example ...
Page 340: ...15 26 MCF5282 User s Manual MOTOROLA SDRAM Example ...
Page 356: ...16 16 MCF5282 User s Manual MOTOROLA DMA Controller Module Functional Description ...
Page 408: ...17 52 MCF5282 User s Manual MOTOROLA Buffer Descriptors ...
Page 446: ...20 24 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 474: ...22 18 MCF5282 User s Manual MOTOROLA Programming Model ...
Page 510: ...23 36 MCF5282 User s Manual MOTOROLA Operation ...
Page 526: ...24 16 MCF5282 User s Manual MOTOROLA I2C Programming Examples ...
Page 672: ...28 12 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 718: ...29 46 MCF5282 User s Manual MOTOROLA Motorola Recommended BDM Pinout ...
Page 750: ...32 8 MCF5282 User s Manual MOTOROLA Ordering Information ...