DS26514G Maxim Integrated, DS26514G Datasheet - Page 199

• Manufacturer Part Number: DS26514G
• Description: Network Controller & Processor ICs
• Manufacturer: Maxim Integrated

Specifications of DS26514G

• Part # Aliases: 90-26514-G00

10.4.2 Transmit Register Descriptions
10.4.2.1
Register Name:
Register Description:
Register Address:
Bit #
Name
Default
Bit 7 : Number Of Flags Select (NOFS).
Bit 6 : Transmit End of Message and Loop (TEOML). To loop on a message, should be set to a one just before
the last data byte of an HDLC packet is written into the transmit FIFO. The message will repeat until the user clears
this bit or a new message is written to the transmit FIFO. If the host clears the bit, the looping message will
complete then flags will be transmitted until new message is written to the FIFO. If the host terminates the loop by
writing a new message to the FIFO the loop will terminate, one or two flags will be transmitted and the new
message will start. If not disabled via TCRCD, the transmitter will automatically append a two-byte CRC code to the
end of all messages.
Bit 5 : Transmit HDLC-64 Reset (THR). Will reset the transmit HDLC-64 controller and flush the transmit FIFO. An
abort followed by 7Eh or FFh flags/idle will be transmitted until a new packet is initiated by writing new data into the
FIFO. This is an acknowledged reset, that is, the host need only to set the bit and the DS26514 will clear it once
the reset operation is complete. Total time for the reset is less than 250µs.
Bit 4 : Transmit HDLC-64 Mapping Select (THMS).
Bit 3 : Transmit Flag/Idle Select (TFS). This bit selects the inter-message fill character after the closing and
before the opening flags (7Eh).
Bit 2 : Transmit End of Message (TEOM). Should be set to a one just before the last data byte of an HDLC
packet is written into the transmit FIFO at THF. If not disabled via TCRCD, the transmitter will automatically append
a two byte CRC code to the end of the message.
Bit 1 : Transmit Zero Stuffer Defeat (TZSD). The Zero Stuffer function automatically inserts a zero in the
message field (between the flags) after 5 consecutive ones to prevent the emulation of a flag or abort sequence by
the data pattern. The receiver automatically removes (de-stuffs) any zero after 5 ones in the message field.
Bit 0 : Transmit CRC Defeat (TCRCD). A two-byte CRC code is automatically appended to the outbound
message. This bit can be used to disable the CRC function.
19-5856; Rev 4; 5/11
0 = send one flag between consecutive messages
1 = send two flags between consecutive messages
0 = Normal operation
1 = Reset transmit HDLC-64 controller and flush the transmit FIFO
0 = Transmit HDLC-64 assigned to channels
1 = Transmit HDLC-64 assigned to FDL(T1 mode), Sa Bits(E1 mode). This mode must be enabled with
TCR2.7.
0 = 7Eh
1 = FFh
0 = enable the zero stuffer (normal operation)
1 = disable the zero stuffer
0 = enable CRC generation (normal operation)
1 = disable CRC generation
NOFS
7
0
Transmit HDLC-64 Register Definitions
TEOML
THC1
Transmit HDLC-64 Control Register 1
110h + (200h x (n-1)) : where n = 1 to 4
6
0
THR
5
0
THMS
4
0
TFS
3
0
TEOM
2
0
DS26514 4-Port T1/E1/J1 Transceiver
TZSD
1
0
TCRCD
0
0
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