DS3134 datasheet(85/203 Pages) DALLAS

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DS3134

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Bit 6 / Transmit Corrupt FCS (TCFCS). When this bit is set low, the HDLC engine will allow the

Frame Checksum Sequence (FCS) to be transmitted as generated. When this bit is set high, the HDLC

engine will invert all the bits of the FCS before transmission occurs. This is useful in debugging and

testing HDLC channels at the system level.

0 = generate FCS normally

1 = invert all FCS bits

Bit 7 / Transmit Abort Enable (TABTE). When this bit is set low, the HDLC engine will perform

normally only sending an Abort sequence (eight ones in a row) when an error occurs in the PCI Block or

the FIFO underflows. When this bit is set high, the HDLC engine will continuously transmit an all ones

pattern (i.e. an Abort sequence). This bit is still active when the HDLC engine is configured in the

Transparent Mode (TTRANS = 1).

Bits 8 to 11/ Transmit Flag Generation Bits 0 to 3 (TFG0/TFG1/TFG2/TFG3).

These 4 bits

determine how many flags and interfill bytes will be sent in between consecutive packets.

TFG3

TFG2

TFG1

TFG0

Action

share closing and opening flag

closing flag / no interfill bytes / opening flag

closing flag / 1 interfill bytes / opening flag

closing flag / 2 interfill bytes / opening flag

closing flag / 3 interfill bytes / opening flag

closing flag / 4 interfill bytes / opening flag

closing flag / 5 interfill bytes / opening flag

closing flag / 6 interfill bytes / opening flag

closing flag / 7 interfill bytes / opening flag

closing flag / 8 interfill bytes / opening flag

closing flag / 9 interfill bytes / opening flag

closing flag / 10 interfill bytes / opening flag

closing flag / 11 interfill bytes / opening flag

closing flag / 12 interfill bytes / opening flag

closing flag / 13 interfill bytes / opening flag

closing flag / 14 interfill bytes / opening flag

Bit 12 / Transmit Zero Stuffing Disable (TZSD). When this bit is set low, the HDLC engine will

perform zero stuffing on the outgoing data stream. When this bit is set high, the outgoing data stream is

not zero stuffed. This bit is ignored when the HDLC engine is configured in the Transparent Mode

(TTRANS = 1).

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