Datasheet
Functional Description
Intel® Xeon® Processor D-1500 Product Family 87
Datasheet - Volume 1 of 4: Integrated Platform Controller Hub
March 2015
3.10.3 Stop Frame
After all data frames, a Stop Frame is driven by Intel® Xeon® Processor D-1500
Product Family. The SERIRQ signal is driven low by Intel® Xeon® Processor D-1500
Product Family for 2 or 3 PCI clocks. The number of clocks is determined by the SERIRQ
configuration register. The number of clocks determines the next mode.
3.10.4 Specific Interrupts Not Supported Using SERIRQ
There are three interrupts seen through the serial stream that are not supported by
Intel® Xeon® Processor D-1500 Product Family. These interrupts are generated
internally, and are not sharable with other devices within the system. These interrupts
are:
• IRQ0. Heartbeat interrupt generated off of the internal 8254 counter 0.
• IRQ8#. RTC interrupt can only be generated internally.
• IRQ13. Floating point error interrupt generated off of the processor assertion of
FERR#.
Intel® Xeon® Processor D-1500 Product Family ignores the state of these interrupts in
the serial stream, and does not adjust their level based on the level seen in the
serial stream.
3.10.5 Data Frame Format
Ta b l e 3- 1 8 shows the format of the data frames. For the PCI interrupts (A–D), the
output from Intel® Xeon® Processor D-1500 Product Family is AND’d with the PCI
input signal. This way, the interrupt can be signaled using both the PCI interrupt input
signal and using the SERIRQ signal (they are shared).
Table 3-17. Stop Frame Explanation
Stop Frame Width Next Mode
2 PCI clocks Quiet Mode. Any SERIRQ device may initiate a Start Frame
3 PCI clocks Continuous Mode. Only the host (Intel® Xeon® Processor D-1500 Product Family)
may initiate a Start Frame
Table 3-18. Data Frame Format (Sheet 1 of 2)
Data
Frame #
Interrupt
Clocks Past
Start Frame
Comment
1 IRQ0 2 Ignored. IRQ0 can only be generated using the internal 8524
2IRQ1 5
3 SMI# 8 Causes SMI# if low. Will set the SERIRQ_SMI_STS bit.
4IRQ3 11
5IRQ4 14
6IRQ5 17
7IRQ6 20
8IRQ7 23
9 IRQ8 26 Ignored. IRQ8# can only be generated internally.
10 IRQ9 29
11 IRQ10 32