System Address Mapping
Élan™SC520 Microcontroller User’s Manual
4-11
Figure 4-3
System I/O Map
4.3.4.1
Configuration Base Address (CBAR) Register
The Configuration Base Address (CBAR) register (Port FFFCh) is a 32-bit register that is
used to relocate the integrated memory-mapped peripherals and MMCR registers, thus
allowing a more flexible system memory map. The CBAR is fixed in I/O space at FFFCh
and is “keyed” to prevent accidental programming.
The CBAR allows an alias of the memory-mapped configuration registers (MMCR) to be
aliased anywhere in the first 1 Gbyte of address space on a 4-Kbyte boundary. The MMCR
is always available in the memory space directly below the boot ROM space at FFFEF000h,
but the CBAR can be programmed to optionally allow a copy of this region anywhere in the
lower 1-Gbyte space (on a 4-Kbyte boundary).
4.3.4.2
PCI Configuration Space
PCI Local Bus Specification, Revision 2.2
,
defines an indirect-mapped configuration space
that occupies only eight bytes in I/O space from 0CF8–0CFFh, and this mechanism is
supported in the ÉlanSC520 microcontroller. The PCI bus configuration scheme uses two
32-bit I/O locations:
■
PCI Configuration Address (PCICFGADR) register (Port 0CF8h) is the
address register
where the actual address of the device’s register and the bus number is located.
■
PCI Configuration Data (PCICFGDATA) register (Port 0CFCh) is the
data register where
the data of the specific register is written to or read from.
PC/AT Peripherals
The “holes” default to
external GP bus, but
can be redirected to
PCI bus. See
03FFh
0000h
FFFFh
0
1 Kbyte
64 Kbytes
Default PCI Bus
Space
Can also be
retargeted to GP bus
FFFCh
CBAR
0CFFh
0CF8h
PCI Configuration
Registers
Default PCI Bus
Space
Can also be
retargeted to GP bus
Содержание Elan SC520
Страница 1: ...lan SC520 Microcontroller User s Manual Order 22004A...
Страница 4: ...iv lan SC520 Microcontroller User s Manual...
Страница 28: ...Introduction xxviii lan SC520 Microcontroller User s Manual...
Страница 42: ...Architectural Overview 1 14 lan SC520 Microcontroller User s Manual...
Страница 78: ...System Initialization 3 22 lan SC520 Microcontroller User s Manual...
Страница 108: ...Clock Generation and Control 5 10 lan SC520 Microcontroller User s Manual...
Страница 118: ...Reset Generation 6 10 lan SC520 Microcontroller User s Manual...
Страница 148: ...System Arbitration 8 24 lan SC520 Microcontroller User s Manual...
Страница 214: ...SDRAM Controller 10 36 lan SC520 Microcontroller User s Manual...
Страница 230: ...Write Buffer and Read Buffer 11 16 lan SC520 Microcontroller User s Manual...
Страница 288: ...GP Bus DMA Controller 14 22 lan SC520 Microcontroller User s Manual...
Страница 316: ...Programmable Interval Timer 16 8 lan SC520 Microcontroller User s Manual...
Страница 328: ...Software Timer 18 4 lan SC520 Microcontroller User s Manual...
Страница 346: ...Real Time Clock 20 12 lan SC520 Microcontroller User s Manual...
Страница 360: ...UART Serial Ports 21 14 lan SC520 Microcontroller User s Manual...
Страница 414: ...AMDebug Technology 26 8 lan SC520 Microcontroller User s Manual...