PEB22554 SIEMENS [Siemens Semiconductor Group], PEB22554 Datasheet - Page 270

• Manufacturer Part Number: PEB22554
• Description: ICs for Communications
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Transmit Data Flow
The frames can be transmitted as shown below.
Figure 70
Transmit Data Flow of QuadFALC
Transmitting a HDLC frame via register CMDR.XTF, the address, the control fields and
the data field have to be entered in the XFIFO.
If CCR3.XCRC is set, the CRC checksum will not be generated internally. The checksum
has to be provided via the transmit FIFO (XFIFO) as the last two bytes. The transmitted
frame will be closed automatically only with a (closing) flag.
The QuadFALC does not check whether the length of the frame, i.e. the number of bytes
to be transmitted makes sense or not.
8.1.2
Characteristics: fully transparent
In no HDLC mode, fully transparent data transmission/reception without HDLC framing
is performed, i.e. without FLAG generation/recognition, CRC generation/check, or
bit-stuffing. This feature can be profitably used e.g for:
• Specific protocol variations
• Transmission of a BOM frame
• Test purposes
Data transmission is always performed out of the XFIFO. In transparent mode, the
receive data is shifted into the RFIFO.
Semiconductor Group
Transmit
HDLC
Frame
(XHF)
Extended Transparent Mode
FLAG
ADDRESS
ADDR
XFIFO
CONTROL
270
CTRL
DATA
Operational Description T1 / J1
CHECKRAM
CRC
ITD06456
PEB 22554
FLAG
09.98