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PowerEdge T310 Technical Guide 41
8.7 PCI Interface
The Intel 3420 PCI interface provides a 33 MHz, Revision 2.3 implementation. The Intel 3420 integrates
a PCI arbiter that supports up to four external PCI bus masters in addition to the internal Intel 3420
requests. This allows for combinations of up to four PCI down devices and PCI slots.
8.8 Low Pin Count (LPC) Interface
The Intel 3420 implements an LPC Interface as described in the LPC 1.1 Specification. The Low Pin
Count (LPC) bridge function of the Intel 3420 resides in PCI Device 31:Function 0. In addition to the
LPC bridge interface function, D31:F0 contains other functional units including DMA, interrupt
controllers, timers, power management, system management, GPIO, and RTC.
8.9 Serial Peripheral Interface (SPI)
The Intel 3420 implements an SPI Interface as an alternative interface for the BIOS flash device. An
SPI flash device can be used as a replacement for the FWH, and is required to support Gigabit
Ethernet, Intel Active Management Technology and integrated Intel Quiet System Technology. The Intel
3420 supports up to two SPI flash devices with speed up to 50 MHz utilizing two chip select pins.
8.10 Compatibility Module (DMA Controller, Timer/Counters, Interrupt
Controller)
The DMA controller incorporates the logic of two 82C37 DMA controllers, with seven independently
programmable channels. Channels 0–3 are hardwired to 8-bit, count-by-byte transfers, and channels
5–7 are hardwired to 16-bit, count-by-word transfers. Any two of the seven DMA channels can be
programmed to support fast Type-F transfers.
Channel 4 is reserved as a generic bus master request.
The Intel 3420 supports LPC DMA, which is similar to ISA DMA, through the Intel 3420’s DMA
controller. LPC DMA is handled through the use of the LDRQ# lines from peripherals and special
encoding on LAD[3:0] from the host. Single, Demand, Verify, and Increment modes are supported on
the LPC interface.
The timer/counter block contains three counters that are equivalent in function to those found in one
82C54 programmable interval timer. These three counters are combined to provide the system timer
function, and speaker tone. The 14.31818 MHz oscillator input provides the clock source for these three
counters.
The Intel 3420 provides an ISA-Compatible Programmable Interrupt Controller (PIC) that incorporates
the functionality of two, 82C59 interrupt controllers. The two interrupt controllers are cascaded so that
14 external and two internal interrupts are possible. In addition, the Intel 3420 supports a serial interrupt
scheme.
All of the registers in these modules can be read and restored. This is required to save and restore
system state after power has been removed and restored to the platform.
8.11 Advanced Programmable Interrupt Controller (APIC)
In addition to the standard ISA compatible Programmable Interrupt Controller (PIC) described in the
previous section, the Intel 3420 incorporates the Advanced Programmable Interrupt Controller (APIC).