Motorola ColdFire MCF5281 - Manual (Page 341)

Fast Ethernet Controller (FEC)
Freescale Semiconductor 17-31
Other registers reset when the ECR[ETHER_EN] bit is cleared (which is accomplished by a hard reset or
software to halt operation). By clearing ECR[ETHER_EN], configuration control registers such as the
TCR and RCR are not reset, but the entire data path is reset.
17.5.3 User Initialization (Prior to Setting ECR[ETHER_EN])
You need to initialize portions the FEC prior to setting the ECR[ETHER_EN] bit. The exact values depend
on the particular application. The sequence is not important.
Table 17-32 defines Ethernet MAC registers requiring initialization.
Table 17-33 defines FEC FIFO/DMA registers that require initialization.
Table 17-31. ECR[ETHER_EN] De-Assertion Effect on FEC
Register/Machine Reset Value
XMIT block Transmission is aborted (bad CRC
appended)
RECV block Receive activity is aborted
DMA block All DMA activity is terminated
RDAR Cleared
TDAR Cleared
Descriptor Controller block Halt operation
Table 17-32. User Initialization (Before ECR[ETHER_EN])
Description
Initialize EIMR
Clear EIR (write 0xFFFF_FFFF)
TFWR (optional)
IALR / IAUR
GAUR / GALR
PALR / PAUR (only needed for full duplex flow control)
OPD (only needed for full duplex flow control)
RCR
TCR
MSCR (optional)
Clear MIB_RAM
Table 17-33. FEC User Initialization (Before ECR[ETHER_EN])
Description
Initialize FRSR (optional)
Initialize EMRBR
Initialize ERDSR
Initialize ETDSR
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3