2. Interface Operation
45
Tsi308 User Manual
80D4000_MA001_02
Tundra Semiconductor Corporation
www.tundra.com
•
For level interrupts, the ISR bit is not cleared until an End of Interrupt (EOI) packet is
received with a vector ID matching the ISR. Software may also write a 1 to 63
rd
bit of
Interrupt Definition Register to clear the interrupt without an EOI.
•
All interrupts and interrupt blocks are disabled at reset and must be enabled by software
•
The ISR can also be monitored via the CSRs
2.4.12.1
Interrupt Diagnostic Mode
To simplify debugging interrupt software and hardware, each interrupt may be stimulated and
monitored via CSR reads and writes (see the Interrupt Diagnostic Register for details). Writing a
1 to the Initiate field of the CSR will generate an interrupt on the interrupt line in the Pin
Number field. The ISR bit may be observed by monitoring the Active field of the same CSR.
2.5
PCI-X Arbiter
The Tsi308 includes a PCI-X arbiter for each PCI-X port. The arbiter is an independent unit.
The Tsi308’s internal PCI-X request and PCI-X grant signals are connected to pins as
Px_REQ_OUT_N and Px_GNT_IN_N (x = 0 for PCI A and x = 1 for PCI B). It is possible to
either use this arbiter or to bypass it and use an external arbiter.
The Tsi308’s internal arbiter contains two round-robin arbitration groups: Px_REQ0_N and
Px_REQ1_N through Px_REQ5_N. Within each group, arbitration is shared equally between
the requests. Generally Px_REQ_OUT_N would be attached to Px_REQ0_N and
Px_GNT_IN_N attached to Px_GNT0_N.
When there are no requests present, the arbiter either parks the bus at the last grant or (based on
a CSR bit) at Px_GNT0_N, which is presumed to be the Tsi308’s internal requester.
The PCI Control CSR ParkMaster bit allows the configuration of the internal PCI-X Arbiter
parking.
The Active field is always for the CSR indicated by the Pin Number field
Summary of Contents for TSI308
Page 4: ...4 Tsi308 User Manual 80D4000_MA001_02 Tundra Semiconductor Corporation www tundra com ...
Page 6: ...6 Tsi308 User Manual 80D4000_MA001_02 Tundra Semiconductor Corporation www tundra com ...
Page 20: ...20 Tsi308 User Manual 80D4000_MA001_02 Tundra Semiconductor Corporation www tundra com ...
Page 260: ...Index 260 Tsi308 User Manual 80D4000_MA001_02 Tundra Semiconductor Corporation www tundra com ...