Digi NS9215, Hardware Reference Manual, Page: 281 / 517

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E T H E R N E T C O M M U N I C A T I O N M O D U L E
Ethernet General Control Register #1
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281
D22 R/W ETXDMA 0
Enable transmit DMA
0 Disable transmit DMA data request (use to stall
transmitter)
1 Enable transmit DMA data request
Must be set active high to allow the transmit packet
processor to issue transmit data requests to the AHB
interface.
Set this bit to 0 to temporarily stall frame transmission,
which always stalls at the completion of the current frame.
The 8-bit address of the next buffer descriptor to be read in
the TX buffer descriptor RAM is loaded into the TXSPTR
register when the transmit process ends.
If the transmit packet processor already is stalled and
waiting for TCLER, clearing ETXDMA will not take
effect until TCLER has been toggled.
This bit generally should be set after the Ethernet transmit
parameters (for example, buffer pointer descriptor) are
programmed into the transmit packet processor.
D21 R/W Not used 1 Always write as 1.
D20 R/W Not used 0 Always write as 0.
D19 R/W ERXINIT 0
Enable initialization of RX buffer descriptors
0 Do not initialize
1 Initialize
When set, causes the
RX_RD
logic to initialize the internal
buffer descriptor registers for each of the four pools from
the buffer descriptors pointed to by RXAPTR, RXBPTR,
RXCPTR, and RXDPTR. This is done as part of the RX
initialization process. RXINIT is set in the Ethernet
General Status register when the initialization process is
complete, and ERXINIT must be cleared before enabling
frame reception from the MAC.
The delay from ERXINIT set to RXINIT set is less than
five microseconds.
D18:13 N/A Reserved N/A N/A
D12 R/W Not used 0 Always write as 0.
D11 R/W RXSHFT 0 Shift RX data
0
Standard receive format. No padding bytes added
before receive frame data
1 The receiver inserts 2 bytes of padding before the first
byte of the receive data, to create longword alignment
of the payload.
Bits Access Mnemonic Reset Description