JAJSQ97J may 2009 – january 2021 XIO2001
PRODUCTION DATA
The classic PCI arbiter is configured through the classic PCI configuration space at offset DCh. Table 8-5 identifies and describes the registers associated with classic PCI arbitration mode.
PCI OFFSET | REGISTER NAME | DESCRIPTION |
---|---|---|
Classic PCI configuration register DCh | Arbiter control (see Section 8.4.70) | Contains a two-tier priority scheme for the bridge and six PCI bus devices. The bridge defaults to the high priority tier. The six PCI bus devices default to the low priority tier. A bus parking control bit (bit 7, PARK) is provided. |
Classic PCI configuration register DDh | Arbiter request mask (see Section 8.4.71) | Six mask bits provide individual control to block each PCI Bus REQ input. Bit 7 (ARB_TIMEOUT) in the arbiter request mask register enables generating timeout status if a PCI device does not respond within 16 PCI bus clocks. Bit 6 (AUTO_MASK) in the arbiter request mask register automatically masks a PCI bus REQ if the device does not respond after GNT is issued. The AUTO_MASK bit is cleared to disable any automatically generated mask. |
Classic PCI configuration register DEh | Arbiter time-out status (see Section 8.4.72) | When bit 7 (ARB_TIMEOUT) in the arbiter request mask register is asserted, timeout status for each PCI bus device is reported in this register. |