Datasheet

509
32117D–AVR-01/12
AT32UC3C
• RE: Receive Enable
0: Frame reception stops immediately and the receive FIFO is cleared. The receive queue pointer register is unaffected.
1: Enables the MACB to receive data.
• LLB: Local Loopback
0: Local loopback is disabled.
1: Local loopback is enabled. It connects TXD to RXD, TX_EN to RX_DV, forces full duplex and drives RX_CLK and TX_CLK
with CLK_MACB_PB divided by 4. RX_CLK and TX_CLK may glitch as the MACB is switched into and out of internal loop back.
It is important that receive and transmit circuits have already been disabled when making the switch into and out of internal loop
back. This function may not be supported by some instantiations of the MACB.
• LB: Loopback
0: Loopback is disabled.
1: Loopback is enabled. Asserts the loopback signal to the PHY.