Adaptec 1737100 Programmer Manual - Page 87

Register Descriptions PCI INTPINSEL (Interrupt Pin Select) Register Type: R Internal Registers Subgroup: PCI Configuration Header Byte Address: 3Dh Table 7-24. Interrupt Pin Select Register Reset Bit(s) rw Value Description/Function 7:0 r 1h INTPS[7:0]: The Interrupt Pin register specifies which PCI interrupt pin the device (or device function) uses. The AIC-6915, as a single function PCI device, must use INTA_ and have a default value of 1h. The default value can be changed to a value read from an external serial EEPROM if BR_A1 pin is asserted when PCI_PCIRST_ is deasserted. This feature enables the integration of multiple AIC-6915 devices on the same PCI card (as a multiport Ethernet NIC) and treats the card as one PCI device with multiple functions having different interrupt lines. PCI MINGNT (Minimum Grant) Register Type: R Internal Registers Subgroup: PCI Configuration Header Byte Address: 3Eh Table 7-25. Minimum Grant Register Reset Bit(s) rw Value Description/Function 7:0 r 08h MINGNT[7:0]: The Minimum Grant register indicates the desired PCI_GNT_ asserted period needed to complete burst transfer of the device data buffer, assuming that the intended target does not extend the transfer time by use of PCI_TRDY_. The value read from the register specifies a period of time in units of 0.25 microseconds. The AIC-6915's MINGNT register value is 8h which is the minimum time to burst out 256-byte buffer. The default value can be changed to a value read from an external serial EEPROM if the BR_A1 signal pin is asserted when PCIRST_ is deasserted. 7-15