82801FB Datasheet, PDF (49/786 Pages) Intel Corporation – Intel I/O Controller Hub 6 (ICH6) Family

Introduction
Compatibility Modules (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.
The ICH6 supports LPC DMA, which is similar to ISA DMA, through the ICH6’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. Channels 0–3 are 8-bit channels. Channels 5–7 are 16-bit channels. Channel 4 is
reserved as a generic bus master request.
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 ICH6 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 ICH6 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.
Advanced Programmable Interrupt Controller (APIC)
In addition to the standard ISA compatible Programmable Interrupt controller (PIC) described in
the previous section, the ICH6 incorporates the Advanced Programmable Interrupt Controller
(APIC).
Universal Serial Bus (USB) Controller
The ICH6 contains an Enhanced Host Controller Interface (EHCI) compliant host controller that
supports USB high-speed signaling. High-speed USB 2.0 allows data transfers up to 480 Mb/s
which is 40 times faster than full-speed USB. The ICH6 also contains four Universal Host
Controller Interface (UHCI) controllers that support USB full-speed and low-speed signaling.
The ICH6 supports eight USB 2.0 ports. All eight ports are high-speed, full-speed, and low-speed
capable. ICH6’s port-routing logic determines whether a USB port is controlled by one of the
UHCI controllers or by the EHCI controller. See Section 5.19 and Section 5.20 for details.
LAN Controller
The ICH6’s integrated LAN controller includes a 32-bit PCI controller that provides enhanced
scatter-gather bus mastering capabilities and enables the LAN controller to perform high speed
data transfers over the PCI bus. Its bus master capabilities enable the component to process high-
level commands and perform multiple operations; this lowers processor utilization by off-loading
communication tasks from the processor. Two large transmit and receive FIFOs of 3 KB each help
prevent data underruns and overruns while waiting for bus accesses. This enables the integrated
LAN controller to transmit data with minimum interframe spacing (IFS).
Intel^® I/O Controller Hub 6 (ICH6) Family Datasheet
49