UPD72874 データシートの表示（PDF） - NEC => Renesas Technology
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UPD72874 Datasheet PDF : 40 Pages
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µPD72874
3.1.1 Offset_00 Vendor ID Register
This register identifies the manufacturer of the µPD72874. The ID is assigned by the PCI_SIG committee.
Bits
15-0
R/W
R
Constant value of 1033H.
Description
3.1.2 Offset_02 Device ID Register
This register identifies the type of the device for the µPD72874. The ID is assigned by NEC Corporation.
Bits
15-0
R/W
R
Constant value of 00F2H.
Description
3.1.3 Offset_04 Command Register
The register provides control over the device’s ability to generate and respond to PCI cycles.
Bits
0
1
2
3
4
5
6
7
8
9
15-10
R/W
Description
R
I/O enable Constant value of 0. The µPD72874 does not respond to PCI I/O accesses.
R/W
Memory enable Default value of 1. It defines if the µPD72874 responds to PCI memory
accesses. This bit should be set to one upon power-up reset.
0: The µPD72874 does not respond to PCI memory cycles
1: The µPD72874 responds to PCI memory cycles
R/W
Master enable Default value of 1. It enables the µPD72874 as bus-master on the PCI-bus.
0: The µPD72874 cannot generate PCI accesses by being a bus-master
1: The µPD72874 is capable of acting as a bus-master
R
Special cycle monitor enable Constant value of 0. The special cycle monitor is always
disabled.
R/W
Memory write and invalidate enable Default value of 0. It enables Memory Write and Invalid
Command generation.
0: Memory write must be used
1: The µPD72874, when acts as PCI master, can generate the command
R
VGATM color palette invalidate enable Constant value of 0. VGA color palette invalidate is
always disabled.
R/W
Parity error response Default value of 0. It defines if the µPD72874 responds to PERR.
0: Ignore parity error
1: Respond to parity error
R
Stepping enable Constant value of 0. Stepping is always disabled.
R/W
System error enable Default value of 0. It defines if the µPD72874 responds to SERR.
0: Disable system error checking
1: Enable system error checking
R
Fast back-to-back enable Constant value of 0. Fast back-to-back transactions are only
allowed to the same agent.
R
Reserved Constant value of 000000.
Preliminary Data Sheet S15306EJ2V0DS
19
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