Chapter 11. Ethernet Module
11-31
Programming Model
As soon as the FEC is initialized and enabled, it operates autonomously. Typically, the
driver writes only to R_DES_ACTIVE, X_DES_ACTIVE, and I_EVENT 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
Table 11-31.
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 11-32.
Table 11-30. Hardware Initialization
User/System
Register/Machine
Reset Value
User
ECNTRL
Cleared
I_EVENT
Cleared
I_MASK
Cleared
MII_SPEED
Cleared
System
MII State Machine
Prevent conflict on MII_DATA
Table 11-31. I ETHER_EN = 0
Location Effect
System
DMA block
All DMA activity is terminated
XMIT block
Transmission is Aborted
User
R_DES_ACTIVE
Cleared
X_DES_ACTIVE
Cleared
Table 11-32. User Initialization Process (before ETHER_EN)
Step Description
1
Set I_MASK
2
Clear I_EVENT
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
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Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...