Intel PXA26X User Manual download pdf (Page 252)

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6-62 Intel® PXA26x Processor Family Developer’s Manual

Memory Controller

Figure 6-24. 16-Bit PC Card Memory Map

The 16-bit PC Card Memory Map space is divided into eight partitions, four for each card slot. The

four partitions for each card slot are: common memory, I/O, attribute memory, and a reserved

space. Each partition starts on a 64-Mbyte boundary.

During an access, pins MA[25:0], nPREG, and PSKTSEL are driven at the same time. nPCE1 and

nPCE2 are driven concurrently with the address signals for common memory and attribute-

memory accesses. For I/O accesses, their value depends on the value of nIOIS16 and is valid a

fixed amount of time after nIOIS16 is valid.

Common memory and attribute memory accesses assert the nPOE or nPWE control signals. I/O

accesses assert the nIOR or nIOW control signals and use the nIOIS16 input signal to determine

the bus width of the transfer (8 or 16 bits). The PXA26x processor family uses nPCE2 to indicate to

the expansion device that the upper half of the data bus (MD[15:8]) are used for the transfer, and

nPCE1 to indicate that the lower half of the data bus (MD[7:0]) are used. nPCE1 and nPCE2 are

asserted for 16-bit accesses.

Refer to Table 6-32 through Table 6-39 for signal combinations during common memory, I/O, and

attribute accesses.

When writes goes to a card sockets and a byte has been masked via an internal byte enable, the

write does not occur on the external bus. For reads, one half-word is always read from the socket,

even if only 1 byte is requested. In some cases, based on internal address alignment, one word is

read, even if only 1 byte is requested.

All DMA modes are supported in the card interface increment the address.

Socket 1 Common Memory Space

Socket 1 Attribute Memory Space

Socket 1 I/O Space

Socket 0 Common Memory Space

Socket 0 Attribute Memory Space

Socket 0 I/O Space

Reserved

0x3C00 0000

0x3800 0000

0x3400 0000

0x3000 0000

0x2C00 0000

0x2800 0000

0x2400 0000

0x2000 0000

1 2 ... 247 248 249 250 251 252 253 254 255 256 257 ... 623 624

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