
QuadFALC
TM
PEF 22554 E
Functional Description T1/J1
Data Sheet
180
Rev. 1.2, 2006-01-26
To relieve the micro controller load from always reading the complete RS(12:1) buffer every 3 ms the QuadFALC
TM
notifies the micro controller by interrupt ISR0.RSC only when signaling changes from one multiframe to the next.
This interrupt can be suppressed for “cleared channels” by setting register bit CCR1.RSCC. Additionally the
QuadFALC
TM generates a receive signaling data change pointer (RSP1/2) which directly points to the updated
RS(12:1) register.
Internal multiplexing of data and signaling data can be disabled on a per time slot basis (clear channel capability).
This is also valid when using the internal and external signaling mode.
5.3.3.4
Parallel Transmit CAS Bit-Robbing (T1/J1)
The CAS information is taken from the registers XS(12:1). So the CAS information is controllable by the micro
controller over the asynchronous, SPI or SCI interlace. The signaling controller inserts the CAS bit stream on the
transmit line side.
5.3.4
Bit Oriented Messages (BOM) in ESF-DL Channel (T1/J1)
The QuadFALC
TM HDLC controller 1 of each of the four channels supports the DL-channel protocol for ESF format
according to ANSI T1.403 specification or according to AT&T TR54016. Bit oriented messaging (BOM) is an Out-
band signaling method.
The QuadFALC
TM HDLC controller 1 supports detection of loop back BOM messages and automatic loop
The BOM code has the following format: “11111111 0xxxxxxx0
B” were the first bit of every byte is the MSB and
the last is the LSB. (“11111111
B” is the BOM flag.) Sending is done as for HDLC, this means LSB first, so
“1111111
B” first. Note that this is consistent to the note 1) in the ANSI T1.403 specification: “rightmost bit
transmitted first”.
Note: The data written into the XFIFO and read out of the RFIFO have to be bitwise mirrored to get the
corresponding bit oriented codes defined in the ANSI T1.403 specification.
The HDLC and bit oriented message (BOM) receiver of the HDLC/BOM controller 1 can be switched on
independent from another by setting the register bits MODE.HRAC and MODE.BRAC respectively. If the
QuadFALC
TM is used for HDLC formats only, the BOM receiver has to be switched off.
Storing of received DL-bit information in the receive FIFO (RFIFO, up to 128 byte deep) of the signaling controller
and transmitting the XFIFO contents in the DL-bit positions is enabled by CCR1.EDLX,EITS = 10
Bytes starting or ending with a 1 are not stored.
Three different BOM reception modes can be programmed by CCR1.BRM and CCR2.RBFE (CCR1_T, CCR2_T):
10 byte packet mode: CCR1.BRM = 0
B: After storing 10 BOM bytes into the RFIFO the receive status byte
marking a BOM frame (RSIS.HFR) is added as the eleventh byte and an interrupt ISR0.RME is generated. The
sampling of data bytes continues and interrupts are generated every tenth bytes until the HDLC flag is
detected.
Continuos reception: CCR1.BRM = 1
B : Interrupts are generated every 64, 32, 16 4 or 2 bytes, dependent on
the configured RFIFO depth (see Chapter 3.4.3). After detecting a HDLC flag, byte sampling is stopped, the
content of the status register RSIS is stored in the RFIFO and an interrupt ISR0.RME is generated.
Continuos reception with 7 out of 10 filter mode: CCR1.BRM = 1
B and CCR2.RBFE = 1B: If CCR2.RFBE is set,
the BOM receiver accepts only BOM frames after detecting 7 out of 10 equal BOM pattern. The content of the
status register RSIS will not be written into the receive FIFO.
Switching between these modes is possible at any time.
Automatic switching between HDLC and BOM (if both MODE.BRAC and MODE.HRAC are set) will be done in the
following way:
After reset the HDLC/BOM controller is in HDLC mode.
After eight consecutive ones (FF
H) were received: switching to BOM mode (note that eight consecutive ones
are also an HDLC abort)
After one HDLC flag (7E
H) was received: switching to HDLC mode (directly, additional HDLC flags are not
necessary)
A sequence FF
H, 7EH is treated as a HDLC start flag