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MPC8240 Integrated Processor User’s Manual
Configuration Register Access
byte-swap the CONFIG_ADDR and CONFIG_DATA values before performing an access
(that is, software loads the configuration register address and the configuration register data
into the processor register in ascending byte order—LSB to MSB).
Note that in the following examples, the data in the configuration register (at 0xA8) is
shown in little-endian order. This is because all the internal registers are intrinsically
little-endian.
Example: Map B address map configuration sequence, 4-byte data write to register at
address offset 0xAA using store word with byte reversed instructions
Initial values:r0 contains 0x8000_00A8
r1 contains 0xFEC0_0000
r2 contains 0xFEE0_0000
r3 contains 0xAABB_CCDD
Register at 0xA8 contains 0xFFFF_FFFF (AB to A8)
Code sequence:
stwbrx
r0,0,r1
sync
stwbrx
r3,0,r2
sync
Results:Address 0xFEC0_0000 contains 0x8000_00A8 (MSB to LSB)
Register at 0xA8 contains 0xAABB_CCDD (AB to A8)
Example: Map B address map configuration sequence, 2-byte data write to register at
address offset 0xAA, using byte-swapped values in the processor registers
Initial values:r0 contains 0xA800_0080
r1 contains 0xFEC0_0000
r2 contains 0xFEE0_0000
r3 contains 0xDDCC_BBAA
Register at 0xA8 contains 0xFFFF_FFFF (AB to A8)
Code sequence:
stw
r0,0(r1)
sync
sth
r3,2(r2)
sync
Results:Address 0xFEC0_0000 contains 0x8000_00A8 (MSB to LSB)
Register at 0xA8 contains 0xAABB_FFFF (AB to A8)
Example: Map A configuration sequence, 2-byte data write to register at address offset
0xA8, using store with byte-reversed instructions
Initial values:r0 contains 0x8000_00A8
r1 contains 0x8000_0CF8
r2 contains 0xAABB_CCDD
r3 contains 0x8000_0CFC
Register at 0xA8 contains 0xFFFF_FFFF (AB to A8)
Code sequence:
stwbrx
r0,0,r1
sync
sthbrx
r2,0,r3
sync
Results:Address 0x8000_0CF8 contains 0x8000_0004 (MSB to LSB)
Register at 0xA8 contains 0xFFFF_CCDD (AB to A8)
Summary of Contents for MPC8240
Page 1: ...MPC8240UM D Rev 1 1 2001 MPC8240 Integrated Processor User s Manual ...
Page 38: ...xviii MPC8240 Integrated Processor User s Manual TABLES Table Number Title Page Number ...
Page 48: ...xlviii MPC8240 Integrated Processor User s Manual Acronyms and Abbreviations ...
Page 312: ...6 94 MPC8240 Integrated Processor User s Manual ROM Flash Interface Operation ...
Page 348: ...7 36 MPC8240 Integrated Processor User s Manual PCI Host and Agent Modes ...
Page 372: ...8 24 MPC8240 Integrated Processor User s Manual DMA Register Descriptions ...
Page 394: ...9 22 MPC8240 Integrated Processor User s Manual I2O Interface ...
Page 412: ...10 18 MPC8240 Integrated Processor User s Manual Programming Guidelines ...
Page 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Page 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Page 516: ...16 14 Watchpoint Trigger Applications ...
Page 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
Page 546: ...C 8 MPC8240 Integrated Processor User s Manual ...
Page 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...