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GD32F20x User Manual
839
These bits configure the threshold of the pause timer for retransmitting frames
automatically. Application must make sure the low threshold bits are greater than 0
and less than configured pause time. The low threshold calculation formula is PTM-
PLTS. For example, if PTM = 0x80 (128 slot-times), and PLTS = 0x1 (28 slot-times),
then the second pause frame is automatically transmitted when pause timer
counted at 100 (128 - 28) slot-times after the first pause frame is transmitted
0x0: Pause time minus 4 slot times
0x1: Pause time minus 28 slot times
0x2: Pause time minus 144 slot times
0x3: Pause time minus 256 slot times
Note:
One slot time equals the time of transmitting 512 bits on the MII interface
3
UPFDT
Unicast pause frame detect bit
0: Only the unique multicast address for pause frame which is specified in
IEEE802.3 can be detected.
1: Besides the unique multicast address, MAC can also use the MAC0 address
(ENET_MAC_ADDR0H and ENET_MAC_ADDR0L register) to detecting pause
frame.
2
RFCEN
Receive flow control enable bit
0: Decode function for pause frame is disabled
1: Enable decoding function for the received pause frame and process it. The MAC
disables its transmitter for a specified (pause time field value in received frame)
time
1
TFCEN
Transmit flow control enable bit
0: Disable the flow control operation in the MAC. Both pause frame sending in Full-
duplex mode and back-pressure feature in Half-duplex mode are not performed.
1: Enable the flow control operation in the MAC. Both pause frame sending in Full-
duplex mode and back-pressure feature in Half-duplex mode can be performed by
transmitter.
0
FLCB/BKPA
Flow control busy/back pressure activate bit
This bit only valid when TFCEN is set.
This bit can send a pause frame in Full-duplex mode or activate the back pressure
function in Half-duplex mode by application.
For Full-duplex mode, application must make sure this bit is 0 before writing
ENET_MAC_FCTL register. After set by application, MAC sends a pause frame to
interface and this bit will keep set until the pause frame has completed transmitting.
For Half-duplex mode, MAC can enter back-pressure state by application setting
this bit. When the MAC is in back-pressure state, any frame presented on interface
will make the MAC send a JAM pattern to inform outside a collision occurred.
27.4.8.
MAC flow control threshold register (ENET_MAC_FCTH)
Address offset: 0x1080
Summary of Contents for GD32F20 Series
Page 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Page 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Page 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Page 385: ...GD32F20x User Manual 385 ...
Page 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...