SAB82538 Datasheet, PDF (80/253 Pages) Infineon Technologies AG – ICs for Communications

SAB 82538
SAF 82538
2.5.3 Data Transmission
Transmission of data written to XFIFO is initiated after the Transmit Frame command
(XF) is issued (the LSB is sent out first). Additionally, the CTS signal may be used to
control data transmission. Further data is requested by interrupt (XPR) or DMA. The
message frame is assembled by appending all data characters to the specified SYN
character(s) until Transmit Message End is detected (XME command in interrupt mode,
or, in DMA mode, when the number of characters specified in XBCH, XBCL have been
transferred). Internally generated parity information may be added to each character
(SYN, CRC and Preamble characters are excluded).
If enabled via CRC Append bit (CAPP), the internally calculated CRC checksum (16 bit)
is added to the message frame. Selection between CRC-16 and CRC-CCITT algorithms
is provided. For all characters which have to be included into CRC calculation, the CON
flag has to be set to “1”. This flag which controls the CRC generator is FIFOed together
with each character. There is no need to modify CON for every character loaded if
continuous characters are to be either included into or excluded from CRC calculation.
Note that
– internally generated SYN characters are always excluded from CRC calculation,
– CRC checksum (2 bytes) is sent without parity.
The internal CRC generator is automatically initialized before transmission of a new
frame starts. The initialization value is selectable.
After finishing data transmission, Interframe Timefill (SYN characters or IDLE) is
automatically sent.
Semiconductor Group
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