KADAK KwikNet MPC5200, Руководство пользователя

Страница: 25 / 28

MPC5200 FEC Device Driver
KADAK
M5200E-3
MPC5200 FEC Ethernet
Device Driver Data Sheet
(continued)
Parameters (
continued
)
Ethernet Address The 48-bit Ethernet address assigned to the network must be
defined. The most significant byte (see
MSB
in diagram) of the high 16
bits of the Ethernet address will be transmitted first; the least significant
byte (see
LSB
in diagram) of the low 32 bits of the address will be
transmitted last.
IRQ-BC, IRQ-FEC Parameter
IRQ-BC
is the
KwikNet
IRQ identifier which defines how
the BestComm Ethernet receive task interrupt requests are vectored.
Parameter
IRQ-FEC
is the
KwikNet
IRQ identifier which defines how the
FEC interrupt request is vectored. These parameters are used by the board
driver module
KN_BOARD.C
to map logical device interrupts to the
underlying target hardware and operating system.
Note that device interrupts to the PowerPC are funneled through one or
more PowerPC exception vectors. Multiple devices can generate
interrupts through a single PowerPC exception vector.
AMX PPC
32
handles the separation of interrupts and their vectoring
through a single linear array referred to as the AMX Vector Table.
Consequently, when using
KwikNet
with AMX PPC
32
, the AMX vector
numbers are used as the
KwikNet
IRQ identifiers.
If you are using the
KwikNet
Porting Kit, the assignment of IRQ identifiers
must be done by you as part of your overall system design.
Buffers These parameters define the number of transmit and receive buffers which
the BestComm DMA Engine must be configured to support. Descriptors
for these transmit and receive buffers will be allocated in the BestComm
Buffer Descriptor Tables. Unless you edit the definitions in header file
M5200E.H
, you must specify a minimum of one transmit buffer and two
receive buffers. Two transmit buffers and eight receive buffers are
frequently sufficient.
BestComm FEC descriptors can only be allocated once. Hence, the
descriptors are allocated the first time that the network interface is opened.
For prebuilt networks, the descriptors will be allocated the first time that
KwikNet
is started. For networks added at runtime, the descriptors will be
allocated upon your first call to
KwikNet
procedure
kn_ifopen()
after
having added a network interface with a call to
kn_ifadd()
.