mcf5272 Freescale Semiconductor, Inc, mcf5272 Datasheet - Page 255

• Manufacturer Part Number: mcf5272
• Description: Mcf5272 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

MOTOROLA
values depend on the particular application. The sequence is similar to the procedure
defined in Table 11-32.
11.5.24 FEC Initialization
In the FEC, the descriptor control machine initializes a few registers whenever the
ETHER_EN control is asserted. The transmit and receive FIFO pointers are reset, the
transmit backoff random number is initialized, and the transmit and receive blocks are
activated. After the FEC initialization sequence is complete, the hardware is ready for
operation, waiting for RDAR and TDAR to be asserted by the user.
11.5.24.1 User Initialization (after setting ETHER_EN)
The user initializes portions of the FEC after setting ETHER_EN. The exact values depend
on the particular application. The sequence probably resembles the steps shown in
Table 11-33, though these could also be done before asserting ETHER_EN.
Table 11-32. User Initialization Process (before ETHER_EN)
Step
Step
10
11
12
13
14
15
1
2
3
4
5
6
7
8
9
1
2
Table 11-33. User Initialization (after ETHER_EN)
Fill Receive Descriptor Ring with Empty Buffers
Chapter 11. Ethernet Module
Set IVSR (define ILEVEL)
Initialize (Empty) RxBD
Initialize (Empty) TxBD
Set MAUR and MALR
Set HTUR and HTLR
Set MSCR (optional)
Set FRSR (optional)
Set TFSR (optional)
Description
Description
Set EMRBR
Set ERDSR
Set ETDSR
Set RDAR
Set EIMR
Clear EIR
Set RCR
Set TCR
Programming Model
11-31