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Preliminary Data Sheet S13925EJ2V0DS00
26
μ
PD72870,72871
3.1.5 Offset_08 Revision ID Register
This register specifies a revision number assigned by NEC Corporation for the
μ
PD72870, 72871.
Bits
R/W
Description
7-0
R
Default value of 01H. It specifies the silicon revision. It will be incremented for subsequent
silicon revisions.
3.1.6 Offset_09 Class Code Register
This register identifies the class code, sub-class code, and programming interface of the
μ
PD72870, 72871.
Bits
R/W
Description
7-0
R
Constant value of 10H.
It specifies an IEEE1394 OpenHCI-compliant Host Controller.
15-8
R
Constant value of 00H. It specifies an “IEEE1394” type.
23-16
R
Constant value of 0CH. It specifies a “Serial Bus Controller”.
3.1.7 Offset_0C Cache Line Size Register
This register specifies the system cache line size, which is PC-host system dependent, in units of 32-bit words.
The following cache line sizes are supported: 2, 4, 8, 16, 32, 64, and 128. All other values will be recognized as 0,
i.e. cache disabled.
Bits
R/W
Description
7-0
R/W
Default value of 00H.
3.1.8 Offset_0D Latency Timer Register
This register defines the maximum amount of time that the
μ
PD72870, 72871 is permitted to retain ownership of
the bus after it has acquired bus ownership and initiated a subsequent transaction.
Bits
R/W
Description
7-0
R/W
Default value of 00H. It specifies the number of PCI-bus clocks that the
μ
PD72870, 72871 may
hold the PCI bus as a bus-master.
3.1.9 Offset_0E Header Type Register
Bits
R/W
Description
7-0
R
Constant value of 00H.
It specifies a single function device.
3.1.10 Offset_0F BIST Register
Bits
R/W
Description
7-0
R
Constant value of 00H.
It specifies whether the device is capable of Built-in Self Test.