Datasheet
PIC32MX5XX/6XX/7XX
DS60001156H-page 292 2009-2013 Microchip Technology Inc.
bit 7 AUTOFC: Automatic Flow Control bit
1 = Automatic Flow Control is enabled
0 = Automatic Flow Control is disabled
Setting this bit will enable automatic Flow Control. If set, the full and empty watermarks are used to
automatically enable and disable the Flow Control, respectively. When the number of received buffers
BUFCNT (ETHSTAT<16:23>) rises to the full watermark, Flow Control is automatically enabled. When
the BUFCNT falls to the empty watermark, Flow Control is automatically disabled.
This bit is only used for Flow Control operations and affects both TX and RX operations.
bit 6-5 Unimplemented: Read as ‘0’
bit 4 MANFC: Manual Flow Control bit
1 = Manual Flow Control is enabled
0 = Manual Flow Control is disabled
Setting this bit will enable manual Flow Control. If set, the Flow Control logic will send a PAUSE frame
using the PAUSE timer value in the PTV register. It will then resend a PAUSE frame every 128 *
PTV<15:0>/2 TX clock cycles until the bit is cleared.
Note: For 10 Mbps operation, TX clock runs at 2.5 MHz. For 100 Mbps operation, TX clock runs at
25 MHz.
When this bit is cleared, the Flow Control logic will automatically send a PAUSE frame with a 0x0000
PAUSE timer value to disable Flow Control.
This bit is only used for Flow Control operations and affects both TX and RX operations.
bit 3-1 Unimplemented: Read as ‘0’
bit 0 BUFCDEC: Descriptor Buffer Count Decrement bit
The BUFCDEC bit is a write-1 bit that reads as ‘0’. When written with a ‘1’, the Descriptor Buffer Counter,
BUFCNT, will decrement by one. If BUFCNT is incremented by the RX logic at the same time that this bit
is written, the BUFCNT value will remain unchanged. Writing a ‘0’ will have no effect.
This bit is only used for RX operations.
REGISTER 24-1: ETHCON1: ETHERNET CONTROLLER CONTROL REGISTER 1 (CONTINUED)
Note 1: It is not recommended to clear the RXEN bit and then make changes to any RX related field/register. The
Ethernet Controller must be reinitialized (ON cleared to ‘0’), and then the RX changes applied.