LH79524/LH79525 User’s Guide Ethernet MAC Controller
Version 1.0 6-23
12 RETRY
Retry Test Must be programmed to 0 for normal operation. If programmed to 1, the
delay between collisions will always be one slot time. Setting this bit to 1 helps testing
the ‘Too Many Entries’ condition. Also used in the Pause Frame tests to reduce the
Pause Counter’s decrement time from 512 bit times, to every ETHERRXCLK cycle.
1 = Delay one slot time upon collision
0 = Normal operation
11:10 DIV
Divisor Program according to HCLK speed. This determines the HCLK divisor to gen-
erate ETHERMDC. For conformance with the IEEE 802.3 specification, MDC must not
exceed 2.5 MHz (ETHERMDC is only active during MDIO read and write operations).
00 = Divide HCLK by 8 (for HCLK up to 20 MHz)
01 = Divide HCLK by 16 (for HCLK up to 40 MHz)
10 = Divide HCLK by 32 (for HCLK up to 80 MHz)
11 = Invalid
9///Reserved Reading returns 0. Write the reset value.
8 RECBYTE
Receive 1,536 Byte Frames Specifies if receive frames up to 1,536 bytes in
length are allowed instead of rejecting any frame longer 1,518 bytes.
1 = Allow receive frames with up to 1,536 bytes
0 = Reject frames longer than 1,518 bytes
7 UNIHASHEN
Unicast Hash Enable Configures EMAC to receive unicast frames when the six-bit
hash function of the destination address points to a bit that is set in the hash register.
1 = Receive unicast frames when hash function active
0 = Normal operation
6 MULTIHASHEN
Multicast Hash Enable Configures EMAC to receive multicast frames when the six-
bit hash function of the destination address points to a bit that is set in the hash register.
1 = Receive multicast frames when hash function active
0 = Normal operation
5 NOBCAST
No Broadcast Allows configuration of the EMAC so that frames addressed to a
Broadcast address of all 1s will not be received.
1 = Do not receive frames sent to Broadcast address of all 1s
0 = Normal operation
4 CPYFRM
Copy All Frames Allows all valid frames to be received.
1 = Allow reception of all valid frames
0 = Normal operation
3JUMBOFRM
Jumbo Frames Enable acceptance of jumbo frames.
Note: When using jumbo frames, discard the last 4 bytes for transfers of 2047
bytes or less, and discard the last 64 bytes for frames larger than 2047 bytes.
1 = Accept jumbo frames of up to 10,240 bytes
0 = Normal operation
2BITRATE
Bit Rate Allows the interface to be configured for serial operation. Must be pro-
grammed before receive and transmit enable in the NETCTL register. If 1, a serial
interface is configured with transmit data being driven on pin ETHERTX[0] and re-
ceived on pin ETHERRX[0] serially. Also the ETHERCRS and ETHERRXDV pins
are logically ORed together so either may be used as the data valid signal.
1 = Set EMAC to serial operation
0 = Normal operation
1 FULLDUPLEX
Full Duplex Configures the transmit block to ignore the state of collisions and car-
rier sense, and allows receive while transmitting.
1 = Transmitter ignores the state of collision and carrier sense and
allows receive while transmitting
0 = Normal operation
0///Reserved Reading returns 0. Write the reset value.
Table 6-9. NETCONFIG Fields (Cont’d)
BITS NAME FUNCTION
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