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6-62 Intel® PXA255 Processor Developer’s Manual
Memory Controller
6.8.3 16-Bit PC Card Overview
The PXA255 processor 16-bit PC Card interface provides control for one 16-bit PC Card card slot
with a PSKTSEL pin for support of a second slot. The PXA255 processor interface supports 8- and
16-bit peripherals and handles common memory, I/O, and attribute-memory accesses. The duration
of each access is based on the values programmed in the fields in the MCMEMx, MCATTx, and
MCIOx registers. Figure 6-26 shows the memory map for the 16-bit PC Card space.
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 PXA255 processor 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 6-28 through Table 6-35 for signal combinations during common memory, I/O, and
attribute accesses.
Figure 6-26. 16-Bit PC Card Memory Map
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
reserved
0x3C00_0000
0x3800_0000
0x3400_0000
0x3000_0000
0x2C00_0000
0x2800_0000
0x2400_0000
0x2000_0000