DocID018909 Rev 11
RM0090
Ethernet (ETH): media access control (MAC) with DMA controller
1232
Note:
Reading the PMT control and status register automatically clears the Wakeup Frame
Received and Magic Packet Received PMT interrupt flags. However, since the registers for
these flags are in the CLK_RX domain, there may be a significant delay before this update
is visible by the firmware. The delay is especially long when the RX clock is slow (in 10 Mbit
mode) and when the AHB bus is high-frequency.
Since interrupt requests from the PMT to the CPU are based on the same registers in the
CLK_RX domain, the CPU may spuriously call the interrupt routine a second time even after
reading PMT_CSR. Thus, it may be necessary that the firmware polls the Wakeup Frame
Received and Magic Packet Received bits and exits the interrupt service routine only when
they are found to be at ‘0’.
33.8
Ethernet register descriptions
The peripheral registers can be accessed by bytes (8-bit), half-words (16-bit) or words (32-
bits).
33.8.1 MAC
register
description
Ethernet MAC configuration register (ETH_MACCR)
Address offset: 0x0000
Reset value: 0x0000 8000
The MAC configuration register is the operation mode register of the MAC. It establishes
receive and transmit operating modes.
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
Reserved
CSTF
Reserved
WD
JD
Reserved
IFG
CS
D
Reserved
FES
ROD
LM
DM
IP
CO
RD
Reserved
AP
CS
BL
DC
TE
RE
Reserved
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits 31:26 Reserved, must be kept at reset value.
Bit 25
CSTF:
CRC stripping for Type frames
When set, the last 4 bytes (FCS) of all frames of Ether type (type field greater than
0x0600) will be stripped and dropped before forwarding the frame to the application.
Bit 24Reserved, must be kept at reset value.
Bit 23
WD:
Watchdog disable
When this bit is set, the MAC disables the watchdog timer on the receiver, and can receive
frames of up to 16 384 bytes.
When this bit is reset, the MAC allows no more than 2 048 bytes of the frame being received
and cuts off any bytes received after that.
Bit 22
JD:
Jabber disable
When this bit is set, the MAC disables the jabber timer on the transmitter, and can transfer
frames of up to 16 384 bytes.
When this bit is reset, the MAC cuts off the transmitter if the application sends out more than
2 048 bytes of data during transmission.
Bits 21:20 Reserved, must be kept at reset value.