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Section 22 PCI Controller (PCIC)
SH7751 Group, SH7751R Group
Page 936 of 1128
R01UH0457EJ0301 Rev. 3.01
Sep 24, 2013
PCI memory
space address
PCI memory
space
H'FD000000
H'FDFFFFFF
16 Mbytes
31
24 23
0
31
24 23
0
31
24 23
0
PCI address
LOCK identifier
PCIMBR
H'FD
2
00
Figure 22.2 PIO Memory Space Access
I/O Transfers:
This section describes how to access I/O space using PIO transfers. The 256KB
from H'FE240000 to H'FE27FFFF of area P4 (H'1E240000 to H'1E27FFFF in area 7) is allocated
as PCI I/O address space. This space is used for the least significant 18 bits of the PCI address.
The most significant 14 bits (IOBR [31:18]) of the I/O space base register (PCIIOBR) are used as
the most significant 14 bits of the PCI address. These two addresses are combined to specify the
32-bit PCI address.
For transfers to the I/O space, first specify the most significant 14 bits of the PCI address in
PCIIOBR, then access the PCI I/O address space. If within the 256KB space, you can access the
PCI I/O address space consecutively simply by setting the PCIIOBR once. If it is necessary to
access another address space beyond 256KB, set PCIIOBR again.
When performing locked transfers in I/O transfers, set the I/O space lock specification bit (LOCK)
in the PCIIOBR. The I/O space is locked while the LOCK bit is set. The same precautions apply
to LOCK I/O transfers as to LOCK memory transfers.