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Fast Ethernet Controller (FEC)
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor
18-27
18.5.4.5
Ethernet Control Register (ECR)
ECR is a read/write user register, though both fields in this register may be altered by hardware as well.
The ECR is used to enable/disable the FEC.
Figure 18-8. Ethernet Control Register (ECR)
NOTE
The device may be operated with an external Ethernet PHY. However, due
to the shared pin groups, the use of an external PHY limits ADC, interrupt,
and QSPI functionality, and disables the UART0/1 and 16-bit timers (see
).
IPSBAR
Offset: 0x1024 (ECR)
Access: User read/write
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ETHE
R_EN
RESE
T
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 18-16. ECR Field Descriptions
Field
Description
1
ETHER_EN
When this bit is set, the FEC is enabled, and reception and transmission are possible. When this bit
is cleared, reception is immediately stopped and transmission is stopped after a bad CRC is
appended to any currently transmitted frame. The buffer descriptor(s) for an aborted transmit frame
are not updated after clearing this bit. When ETHER_EN is deasserted, the DMA, buffer descriptor,
and FIFO control logic are reset, including the buffer descriptor and FIFO pointers. The ETHER_EN
bit is altered by hardware under the following conditions:
• ECR[RESET] is set by software, in which case ETHER_EN is cleared
• An error condition causes the EIR[EBERR] bit to set, in which case ETHER_EN is cleared
0
RESET
When this bit is set, a hardware reset of the FEC is performed. ETHER_EN is cleared and all other
FEC registers are initialized to their reset values. Also, any transmission/reception currently in
progress is abruptly aborted. This bit is automatically cleared by hardware during the reset sequence.
The reset sequence takes approximately 8 system clock cycles after RESET is written with a 1.
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:MCF52234CVM60,
MCF52235CVM60