2. PCI Interface
38
PowerSpan II User Manual
80A1010_MA001_09
Integrated Device Technology
www.idt.com
illustrates the command encoding for PowerSpan II as PCI target.
The PCI target image decodes and claims PCI transactions and controls how these incoming PCI
transactions are mapped to the destination port on PowerSpan II.
describes the programming model for a PCI Target Image Control register.
Table 4: Command Encoding for Transaction Type
—
PowerSpan II as PCI Target
Px_C/BE#[3:0]
Transaction Type
PowerSpan II Capable
0000
Interrupt Acknowledge
No
0001
Special Cycle
No
0010
I/O Read
No
0011
I/O Write
No
0100
Reserved
N/A
0101
Reserved
N/A
0110
Memory Read
Yes
0111
Memory Write
Yes
1000
Reserved
N/A
1001
Reserved
N/A
1010
Configuration Read
Yes (Type 0 only)
1011
Configuration Write
Yes (Type 0 only)
1100
Memory Read Multiple
Yes
1101
Dual Address Cycle
No
1110
Memory Read Line
Yes
1111
Memory Write and Invalidate
Aliased to Memory Write
Table 5: Programming Model for PCI Target Image Control Register
Bits
Type
Description
Default Setting
IMG_EN
R/W
Enables the PCI target image to decode in the
specified physical address range of memory
space.
Disabled
TA_EN
R/W
Enables address translation (see
Image x Translation Address Register” on
page 274
Disabled