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Ethernet Module
MCF5272 ColdFire
®
Integrated Microprocessor User’s Manual, Rev. 3
Freescale Semiconductor
11-33
11.5.22 Initialization Sequence
This section describes which registers and RAM locations are reset due to hardware reset, which are reset
due to the FEC reset, and what locations the user must initialize before enabling the FEC.
As soon as the FEC is initialized and enabled, it operates autonomously. Typically, the driver writes only
to RDAR, TDAR, and EIR during operation.
11.5.22.1 Hardware Initialization
In the FEC, hardware resets only those registers that generate interrupts to the MCF5272 processor or
cause conflict on bidirectional buses. The registers are reset due to a hardware reset.
Other registers reset whenever the ETHER_EN bit is cleared. Clearing ETHER_EN immediately stops all
DMA and transmit activity after a bad CRC is sent, as shown in
11.5.23 User Initialization (Prior to Asserting ETHER_EN)
The user must initialize portions the FEC prior to setting the ETHER_EN bit. The exact values depend on
the particular application. The sequence is similar to the procedure defined in
Table 11-30. Hardware Initialization
User/System
Register/Machine
Reset Value
User
ECR
Cleared
EIR
Cleared
EIMR
Cleared
MSCR
Cleared
System
MII State Machine
Prevent conflict on MMFR
Table 11-31. ETHER_EN = 0
System/User
Location Effect
System
DMA block
All DMA activity is terminated
XMIT block
Transmission is Aborted
User
RDAR
Cleared
TDAR
Cleared
Table 11-32. User Initialization Process (before ETHER_EN)
Step Description
1
Set EIMR
2
Clear EIR
3
Set IVSR (define ILEVEL)
4
Set FRSR (optional)
5
Set TFSR (optional)
6
Set MAUR and MALR