4−18
4.21 Interrupt Event Register
The interrupt event set/clear register reflects the state of the various TSB12LV26 interrupt sources. The interrupt bits
are set to 1 by an asserting edge of the corresponding interrupt signal or by writing a 1 in the corresponding bit in the
set register. The only mechanism to clear a bit in this register is to write a 1 to the corresponding bit in the clear register.
This register is fully compliant with the 1394 Open Host Controller Interface Specification, and the TSB12LV26 device
adds a vendor-specific interrupt function to bit 30. When the interrupt event register is read, the return value is the
bit-wise AND function of the interrupt event and interrupt mask registers. See Table 4−15 for a complete description
of the register contents.
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
Name Interrupt event
Type R RSC R R R RSCU RSCU RSCU RSCU RSCU RSCU RSCU RSCU R RSCU RSCU
Default 0 X 0 0 0 X X X X X X X X 0 X X
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Name Interrupt event
Type R R R R R R RSCU RSCU RU RU RSCU RSCU RSCU RSCU RSCU RSCU
Default 0 0 0 0 0 0 X X X X X X X X X X
Register: Interrupt event
Type: Read/Set/Clear/Update, Read/Set/Clear, Read/Update, Read-only
Offset: 80h set register
84h clear register [returns the contents of the interrupt event register bit-wise ANDed with
the interrupt mask register when read]
Default: XXXX 0XXXh
Table 4−15. Interrupt Event Register Description
BIT FIELD NAME TYPE DESCRIPTION
31 RSVD R Reserved. Bit 31 returns 0 when read.
30 vendorSpecific RSC This vendor-specific interrupt event is reported when either of the general-purpose interrupts are
asserted. The general-purpose interrupts are enabled by setting the corresponding bits INT3_EN
and INT_2EN (bits 31 and 23, respectively) to 1 in the GPIO control register at offset FCh in the PCI
configuration space (see Section 3.23, GPIO Control Register).
29−27 RSVD R Reserved. Bits 29−27 return 0s when read.
26 phyRegRcvd RSCU The TSB12LV26 device has received a PHY register data byte which can be read from bits 23−16
in the PHY layer control register at OHCI offset ECh (see Section 4.30, PHY Layer Control Register).
25 cycleTooLong RSCU If bit 21 (cycleMaster) in the link control register at OHCI offset E0h/E4h (see Section 4.28, Link
Control Register) is set to 1, this indicates that over 125 µs have elapsed between the start of sending
a cycle start packet and the end of a subaction gap. Bit 21 (cycleMaster) in the link control register
is cleared by this event.
24 unrecoverableError RSCU This event occurs when the TSB12LV26 device encounters any error that forces it to stop operations
on any or all of its subunits, for example, when a DMA context sets its dead bit to 1. While bit 24 is
set to 1, all normal interrupts for the context(s) that caused this interrupt are blocked from being set
to 1.
23 cycleInconsistent RSCU A cycle start was received that had values for the cycleSeconds and cycleCount fields that are
different from the values in bits 31−25 (cycleSeconds field) and bits 24−12 (cycleCount field) in the
isochronous cycle timer register at OHCI offset F0h (see Section 4.31, Isochronous Cycle Timer
Register).
22 cycleLost RSCU A lost cycle is indicated when no cycle_start packet is sent or received between two successive
cycleSynch events. A lost cycle can be predicted when a cycle_start packet does not immediately
follow the first subaction gap after the cycleSynch event or if an arbitration reset gap is detected after
a cycleSynch event without an intervening cycle start. Bit 22 may be set to 1 either when a lost cycle
occurs or when logic predicts that one will occur.
21 cycle64Seconds RSCU Indicates that the 7
th
bit of the cycle second counter has changed.
