cx29503 Mindspeed Technologies, cx29503 Datasheet - Page 213

• Manufacturer Part Number: cx29503
• Description: Cx29503 Broadband Access Multiplexer Data Sheet
• Manufacturer: Mindspeed Technologies

CX29503 Data Sheet
0xAE—TDL 1 Status (TDL1_STAT)
Unused bits are reserved and should be written to 0.
TMSG1
TMPTY1
TNEAR1
TFULL1
29503-DSH-002-B
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7
In-Progress Transmit Message—The real-time status of the transmit message sequencer is
provided mostly for diagnostic purposes. During HDLC modes, TMSG1 is high for the
interval between opening and closing Flag characters. This indicates that the transmitter is
actively pulling data bytes from transmit FIFO locations. TMSG1 is low while the channel
transmits Flag or Abort characters. During unformatted and circular buffer modes, TMSG1 is
high continuously.
Transmit FIFO Empty—Indicates no message data is present in the transmit data link FIFO.
This is typically checked by the processor in response to a TMSG or TNEAR interrupt. If this
is a TMSG interrupt, the processor checks TMPTY1 to determine that all queued messages
were sent (TMPTY1 = 1) or more queued messages remain to be sent (TMPTY1 = 0). If this is
a TNEAR interrupt, the processor confirms TMPTY1 = 0 to verify the partial transmit
message was not aborted by a FIFO underrun.
Transmit FIFO-Near Empty—Indicates the data link has emptied the transmit FIFO to below
the near-empty threshold specified in FEC[5:0]. After sending the byte that occupied the near-
empty FIFO threshold level, TNEAR1 goes active-high, which generates a TNEAR interrupt.
The processor must write data to TDL1 to fill the transmit FIFO beyond the near-empty
threshold to clear TNEAR1 status and enable the next TNEAR interrupt event.
Transmit FIFO Full—Indicates the processor has completely filled 64 byte locations in the
transmit FIFO. While TFULL1 remains active, any subsequent processor writes to TDL1 are
ignored. If the processor should inadvertently write to TDL1 while TFULL1 is active, the
processor must allow FIFO to become completely empty without writing to TDL1_EOM to
force the transmitter to send an Abort character.
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6
0 = channel idle
1 = channel actively emptying FIFO
0 = FIFO contains data to be transmitted
1 = FIFO empty
0 = FIFO depth is below the near-empty level
1 = FIFO has been emptied past the near-empty level
0 = FIFO is less than full
1 = FIFO has been completely filled
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5
Mindspeed Technologies™
Preliminary Information
—
4
TMSG1
3
TMPTY1
2
TNEAR1
1
Register Description
TFULL1
0
8
-
83