Advanced Notebook I/O for ISA or LPC Designs
Datasheet
Rev. 0.5 (03-24-05)
Page 142
SMSC SIO10N268
DATASHEET
8.14.1.6 AC/DC Specification Issue
All SER_IRQ agents must drive / sample SER_IRQ synchronously related to the rising edge of PCI bus
clock. The SER_IRQ pin uses the electrical specification of PCI bus. Electrical parameters will follow PCI
spec. section 4, sustained tri-state.
8.14.1.7 Reset and Initialization
The SER_IRQ bus uses PCI_RESET# as its reset signal. The SER_IRQ pin is tri-stated by all agents while
PCI_RESET# is active. With reset, SER_IRQ Slaves are put into the (continuous) IDLE mode. The Host
Controller is responsible for starting the initial SER_IRQ Cycle to collect system’s IRQ/Data default values.
The system then follows with the Continuous/Quiet mode protocol (Stop Frame pulse width) for
subsequent SER_IRQ Cycles. It is Host Controller’s responsibility to provide the default values to 8259’s
and other system logic before the first SER_IRQ Cycle is performed. For SER_IRQ system suspend,
insertion, or removal application, the Host controller should be programmed into Continuous (IDLE) mode
first. This is to guarantee SER_IRQ bus is in IDLE state before the system configuration changes.
8.14.2 Routable IRQ Inputs
The
routable
IRQ
input
(IRQINx)
functions
are
on
pins
53
(GP13/IRQIN1/LED1),
20
(GP23/nLED2/IRQIN2), and 60 (GP20/IRRX2/IRQIN3). The IRQINx pin’s IRQ time slot in the Serial IRQ
stream is selected via a 4-bit control register for each IRQIN function (CR29 for IRQIN1, CR2A for IRQIN2
and IRQIN3). A value of 0000 disables the IRQ function.
NOTE:
In order to use an IRQ for one of the IRQINx inputs that are muxed on the GPIO pins, the corresponding
IRQ must not be used for any of the devices in the SIO10N268. Otherwise contention may occur.
IRQIN1, IRQIN2, and IRQIN3 are capable of generating PME wake events. If an IRQINx pin generates an
event, the associated PME Wake Status bit will be set to ‘1’. The following is a list of the PME status and
enable bits associated with the IRQINx pins.
IRQIN1 will generate an event on bit[3] GP13 of the PME_STS1 register at offset 0x02. If bit[3] GP13
of the PME_EN1 register at offset 0x05 is set to ‘1’ and the PME_EN bit is set to ‘1’ in the PME_EN
register offset 0x01 the IO_PME# pin will be asserted.
IRQIN2 will generate an event on bit[5] GP23 of the PME_STS2 register at offset 0x03. If bit[5] GP23
of the PME_EN2 register at offset 0x06 is set to ‘1’ and the PME_EN bit is set to ‘1’ in the PME_EN
register offset 0x01 the IO_PME# pin will be asserted.
IRQIN3 will generate an event on bit[2] GP20 of the PME_STS2 register at offset 0x03. If bit[2] GP20
of the PME_EN2 register at offset 0x06 is set to ‘1’ and the PME_EN bit is set to ‘1’ in the PME_EN
register offset 0x01 the IO_PME# pin will be asserted.
IRQIN1 and IRQIN2 are capable of generating SMI events. If an IRQINx pin generates an event, the
associated SMI Status bit will be set to ‘1’. The following is a list of the SMI status and enable bits
associated with the IRQINx pins.
IRQIN1 will generate an event on bit[3] GP13 of the SMI_STS1 register at offset 0x08. If bit[3] GP13
of the SMI_EN1 register at offset 0x0A is set to ‘1’ the IO_SMI# pin will be asserted.
IRQIN2 will generate an event on bit[4] GP23 of the SMI_STS2 register at offset 0x09. If bit[4] GP23
of the SMI_EN2 register at offset 0x0B is set to ‘1’ the IO_SMI# pin will be asserted.
NOTE:
IRQIN3 is not capable of generating an SMI event. The edge is programmable through the polarity bit of
the GPIO control register.
Application Note:
If GPIO function is selected on GP13/IRQIN1, GP23/nLED2/IRQIN2, or GP20/IRRX2/IRQIN3 pins and if
IRQ is selected using the routing registers (CR29 for IRQIN1 and CR2A for IRQIN2 and IRQIN3), IRQs will