Fast Ethernet Controller (FEC)
Freescale Semiconductor
16-15
MCF51CN128 Reference Manual, Rev. 6
16.4.10 Physical Address Lower Register (PALR)
PALR contains the lower 32 bits (bytes 0,1,2,3) of the 48-bit address used in the address recognition
process to compare with the DA (destination address) field of receive frames with an individual DA. In
addition, this register is used in bytes 0 through 3 of the 6-byte source address field when transmitting
PAUSE frames. This register is not reset and you must initialize it.
16.4.11 Physical Address Upper Register (PAUR)
PAUR contains the upper 16 bits (bytes 4 and 5) of the 48-bit address used in the address recognition
process to compare with the DA (destination address) field of receive frames with an individual DA. In
addition, this register is used in bytes 4 and 5 of the 6-byte Source Address field when transmitting PAUSE
frames. Bits 15:0 of PAUR contain a constant type field (0x8808) for transmission of PAUSE frames. The
upper 16 bits of this register are not reset and you must initialize it.
1
HBC
Heartbeat control. If set, the heartbeat check performs following end of transmission and the HB bit in the status
register is set if the collision input does not assert within the heartbeat window. This bit should only be modified
when ECR[ETHER_EN] is cleared.
0
GTS
Graceful transmit stop. When this bit is set, MAC stops transmission after any frame currently transmitted is
complete and GRA interrupt in the EIR register is asserted. If frame transmission is not currently underway, the
GRA interrupt is asserted immediately. After transmission finishes, clear GTS to restart. The next frame in the
transmit FIFO is then transmitted. If an early collision occurs during transmission when GTS is set, transmission
stops after the collision. The frame is transmitted again after GTS is cleared. There may be old frames in the
transmit FIFO that transmit when GTS is reasserted. To avoid this, clear ECR[ETHER_EN] following the GRA
interrupt.
Offset: 0x0E4
Access: User read/write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
R
PADDR1
W
Reset — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
Figure 16-11. Physical Address Lower Register (PALR)
Table 16-13. PALR Field Descriptions
Field
Description
31–0
PADDR1
Bytes 0 (bits 31:24), 1 (bits 23:16), 2 (bits 15:8), and 3 (bits 7:0) of the 6-byte individual address are used for exact
match and the source address field in PAUSE frames.
Table 16-12. TCR Field Descriptions (continued)
Field
Description
