Freescale Semiconductor MPC5200B - Manual (Page 500)

Initialization Sequence
MPC5200B Users Guide, Rev. 1
Freescale Semiconductor 14-35
14.9.2 User Initialization (Prior to Asserting ETHER_EN)
The user needs to initialize portions of the FEC prior to setting the ETHER_EN bit. The exact values depend on the particular application; the
sequence of writing the registers is not important. Ethernet MAC registers requiring initialization are defined in
Table 14-41 .
14.9.2.1 Microcontroller Initialization
In the FEC the descriptor control RISC initializes some registers after ETHER_EN is asserted. After the microcontroller initialization
sequence is complete, hardware is ready for operation.
Table 14-42 shows RISC initialization operations common to the FEC.
14.9.3 Frame Control/Status Words
In the FEC transmit frame control words and receive frame status words cross the following the end of frame data. These words are marked
with a type value of 10 and have the following formats.
14.9.3.1 Receive Frame Status Word
Table 14-2 below defines the format for the receive frame status word.
Bits 31-28, 26-25, 19 and 15-11—Reserved
Table 14-41. User Initialization (Before ETHER_EN)
Description
Initialize IMASK
Clear IEVENT (write FFFF_FFFF)
X_WMRK (optional)
IADDR2/IADDR1
GADDR1/GADDR2
PADDR1/PADDR2
OP_PAUSE (only needed for FDX flow control)
R_CNTRL
X_CNTRL
MII_SPEED (optional)
Clear MIB_RAM (locations 200–2FC)
Table 14-42. Microcontroller Initialization (FEC)
Description
Initialize BackOff random number seed
Activate Receiver
Activate Transmit
Table 14-43. Receive Frame Status Word Format
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
0 0 0 0 1
(Last)
0 0 0 BC MC LG NO 0 CR OV TR
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
0 0 0 0 0 FRAME_LENGTH