MPC5200B Users Guide, Rev. 1
14-34 Freescale Semiconductor
Initialization Sequence

14.8.8 FEC Transmit FSM Register—MBAR + 0x31C8

The transmit finite state machine register (XMIT_FSM) controls operation of appending CRC. Typical use is enabled and CRC is appended.
14.9 Initialization Sequence
This section describes which registers are hardware reset, which are reset by the FEC and what locations the user must initialize prior to
enabling the FEC.

14.9.1 Hardware Controlled Initialization

Some registers in the FEC are reset by internal logic. Specifically those registers are control logic that generate interrupts, cause outputs to be
asserted and, in general, configuration control bits.
Other registers are reset when the ETHER_EN bit is not asserted (i.e., cleared). To halt operation ETHER_EN is deasserted by either a hard
reset or by software. By deasserting ETHER_EN configuration control registers such as X_CNTRL and R_CNTRL are not reset, but the entire
data path is reset.
Table14-40 shows the effect deasserting ETHER_EN has on Ethernet MAC operation and registers.
7 RCTL[0] 0 = Disable fec_enable as a reset to FIFO controllers.
1 = Enable fec_enable as a reset to FIFO controllers.
8:31 --- Reserved

Table14-39. FEC Transmit FSM Register

msb 012345678 9 101112131415
RReserved
XFSM[1]
XFSM[0]
Reserved
W
RESET:000000000 0 0 000 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 lsb
RReserved
W
RESET:000000000 0 0 000 0 0
Bits Name Description
0:5 — Reserved
6 XFSM[1] 0 = Do not append CRC.
1 = Append CRC (typical use).
7 XFSM[0] 0 = Disable CRC FSM.
1 = Enable CRC FSM (typical use is enabled).
8:31 --- Reserved

Table14-40. ETHER_EN De-A ssertion Affect on FEC

Register/Machine Reset Value
XMIT block Transmission Aborted (bad CRC appended)
RECV block Receive activity aborted
Tx/Rx FIFO Reset control logic dependent on reset_cntr l

Table 1-1.

Bits Name Description