RadiSys EPS-6315, Hardware Reference Manual, Page: 69 / 123

Chapter 5: Theory of operation
59
• Non-Monarch : The System BIOS configures only the local PCI bus. Setup
allows custom programming of the system resources by providing access to two
memory windows and two memory remap windows within the RadiSys 82600.
Local PCI bus
The EPC-6315 implements a +3.3V, 32 bit local PCI bus. The bus runs at 33 MHz
and has the RadiSys 82600 chipset as the central resource. This PCI bus has one
peripheral device connected to it, the Intel 82559 Ethernet controller.
The next table describes on-board device PCI configuration space locations. The
IDSEL pin on each device connects to the listed PCI address pin. To select the
configuration registers of a given device, a PCI Configuration Space access must be
made with the device's corresponding IDSEL address bit set.
PCI Ethernet controller
One Intel 82559 fast Ethernet controller incorporates internal Media Access
Controller (MAC) and Physical Interface (PHY) interfaces providing support for
10BASE-T or 100BASE-TX connections to the front panel RJ45 connector. The
controller uses local PCI interrupt A, ~REQ0/~GNT0 arbitration pairs, and has a
standard PCI 2.1 compliant configuration space allowing system identification and
configuration.
The PHY enables direct connection to the network media using a 25 MHz, 25 ppm
crystal to derive its internal transmit digital clocks. An Intel- defined magnetics
interfaces the PHY with the RJ45 connection (located on the front panel). In
100BASE-TX mode, the analog subsection of the PHY performs these functions:
• Converts received analog data from the RD pair into a digital 125 Mbps stream,
recovering both clock and data.
• Converts a digital 125 Mbps stream into the proper format, and drives it
through the TD pair into the physical medium.
The 82559 drives on-board status LEDs directly.
PCI interrupts
The EPC-6315 has two sets of PIRQ[A:D] interrupts, one set for the local bus
(LPIRQ) and one for the backplane PCI bus (BPIRQ).
Table 5-3. PCI device configuration
Peripheral ~IDSEL Device Function INT
LPCI arbitration
~REQ/~GNT
RadiSys 82600 system
controller/local PCI bridge AD11 0 0 – Internal
EIDE 0 1 D Internal
Backplane PCI bridge
(master only) AD12 1 0 Internal
Intel 82559 Ethernet A
controller AD25 14 0 A 0