Ricoh R5C841 - Manual (Page 27)

R5C841 PCI-CardBus/IEEE 1394/SD Card/Memory Stick/xD/ExpressCard Data Sheet
12345  2004 R EV .1.10 4-2
4.1.8 Memory Stick Control Register Space
The Memory Stick Control registers are 256byte of register assigned to control the Memory Stick.
These registers are used to set for access to the Memory Stick, to give commands and to
read/write data. These are placed in the memory mapped I/O space by the Memory Stick
Register Base Address register.
4.1.9 xD Picture Card Control Register Space
The xD Picture Card Control registers are 256byte of register assigned to control the xD Picture
Card. These registers are used to set for access to the xD Picture Card, to give commands and to
read/write data. These are placed in the memory mapped I/O space by the xD Picture Card
Register Base Address register.
4.2 CardBus Card Configuration Mechanism
The R5C841 provides a mechanism to access to configuration spaces of a CardBus Card, which
is compliant with the PCI specifications. The R5C841 supports functions of changing Type 1 PCI
configuration command into Type 0 CardBus configuration command and transferring them.
4.3 Address Window and Mapping Mechanism
The R5C841 supports two kinds of PCI-Card Bridge Interface functions, and determines
automatically whether an inserted card is a CardBus Card or a 16-bit Card. Each interface can be
set independently.
On the CardBus Card interface, the transaction is implemented by two I/O windows and two
memory map I/Os or a prefetchable memory window that defined in the PCI configuration space.
The CardBus Card address and the PCI system address use a flat address in common. So the
address range specified by a base register and a limit register is forwarded from the PCI to the
CardBus Card. The R5C841 supports a CardBus Master also, so the address forwarding
transaction from the CardBus Card to the PCI or to the other card also is enabled. If the address
of the transaction started on the CardBus is out of the address range, it will be forwarded to the
PCI.
On the 16-bit Card interface, the transaction is implemented by two I/O windows and five memory
windows, which are set by the 16-bit Card Status Control register and are compliant with the
PCIC. The address forwarding transaction is enabled only from PCI to CardBus.
4.3.1 ISA Mode
The R5C841 supports ISA mode for PCI-CardBus Bridge function. Setting ISA enable bit of the
Bridge Control register enables the ISA mode. The ISA mode is applied to the I/O transaction of
particular address range specified by the I/O Base registers and the I/O Limit registers, which are
also in the first 64K Byte of PCI I/O space (0000_0000h-0000_FFFFh).
By enabled the ISA mode, the I/O transaction for the first 256-byte of each 1-Kbyte, which start
address are 0000x000h, 0000x400h, 0000x800h and 0000xC00h, are forwarded from PCI to
CardBus. The last 768-byte is blocked. Conversely, the I/O transaction in the last 768-byte is
forwarded from CardBus to PCI.