SH7751 Group, SH7751R Group
Section 22 PCI Controller (PCIC)
R01UH0457EJ0301 Rev. 3.01
Page 933 of 1128
Sep 24, 2013
Initial order of priority
(transfer by device 1)
PCIC > device 1 > device 2 > device 3 > device 4
Order of priority after transfer
(transfer by PCIC)
PCIC > device 2 > device 3 > device 4 > device 1
Order of priority after transfer
(transfer by device 3)
device 2 > device 3 > device 4 > device 1 > PCIC
Order of priority after transfer
device 2 > device 4 > device 1 > PCIC > device 3
1.
2.
3.
4.
When the PCIC is operating as the host device, the PCIC performs the PCI bus parking (bus
drive when not in use).
When 3 or fewer master devices are connected, set the level of the unused pins of
PCIREQ
[4:1] high.
In non-host mode, the PCI bus arbitration function of the PCIC is disabled. PCI bus arbitration
is performed according to the specifications of the connected PCI bus arbiter. For details, see
section 22.3.6, PCI Bus Arbitration in Non-host Mode.
Configuration Register Access:
The configuration register of external PCI devices can be
accessed when the PCIC is operating as the host device. The PIO address register (PCIPAR) and
PIO data register (PCIPDR) are used to generate a configuration read/write transfer for accessing
the configuration register.
The PCIC supports the configuration mechanism stipulated in the PCI local bus spec.
First, specify in the PCIPAR the address of the configuration register of the external PCI device to
be accessed. See section 22.2, PCIC Register Descriptions, for how to set the PCIPAR.
Next, read data from the PCIPDR or write data to the PCIPDR. Only longword (32-bit) access of
the PCIPDR is supported.
Special Cycle Generation:
When the PCIC operates as the host device, a special cycle is
generated by setting H'8000FF00 in the PCIPAR and writing to the PCIPDR.
Reset Output:
When the PCIC is operating as the host device,
PCIRST
can be used to reset the
PCI bus. See section 22.5, Resetting, for details of
PCIRST
.
Clock Output:
When the PCIC is operating as the host device and the bus clock (CKIO pin) is
selected as the PCI bus clock, not only does the PCIC's PCI bus clock operate using the CKIO
clock but the CKIO clock can also be used as the PCI bus clock. Thus, there is no requirement for
an external PCI clock oscillation circuit.